7T MRI to Detect Changes in Amygdala Functional Connectivity Induced by Light Intervention Therapy
Poster No:
165
Submission Type:
Abstract Submission
Authors:
Yael Jacob1, Lukasz Widziszewski1, Yijuan Zhu1, Mariana Figueiro1, Priti Balchandani1
Institutions:
1Icahn School of Medicine at Mount Sinai, New York, NY
First Author:
Co-Author(s):
Introduction:
Lighting intervention therapy (LIT) has been shown to provide strong benefits for sleep, depression, and agitation in patients with mid-to-late stages of Alzheimer's disease (Figueiro, 2014; Figueiro, 2020). Although not completely understood, the mechanisms by which LIT works in the brain are rooted in how light exposure entrains the biological clock and affects mood and brain circuits. Light may act on the brain through neuroplasticity and neurotransmission specifically on the targets of the intrinsically photosensitive retinal ganglion cells (ipRGCs) in the retina. Specifically, the amygdala is a key target region (Bedrosian, 2017; Blume, 2019; Killgore, 2022). To better understand the mechanisms by which LIT benefits cognition, we performed high-resolution multi-modal 7 Tesla imaging to investigate the impact of LIT on amygdala functional connectivity in mild cognitive impairment (MCI) participants.
Methods:
For this longitudinal study we enrolled 11 participants diagnosed with MCI. Data were acquired on a Siemens Magnetom 7T MRI scanner. All subjects underwent longitudinal anatomical T1-weighted and resting state functional MRI (fMRI) scans pre- and post- active lighting intervention therapy (LIT; N=6) or control (Sham; N=5). Functional images were processed using the multi-echo independent component analysis implemented in the AFNI meica.py toolbox (Kundu, 2012). Each subject's anatomical T1-weighted brain image was segmented using the Desikan-Killiany Atlas (Desikan, 2006) in FreeSurfer.v.6.0 yielding 84 regions of interest (ROIs) and co-registered into fMRI space using SPM12. Functional connectivity (FC) of the left and right amygdala ROIs was assessed by calculating the Pearson correlation between their mean time series and those of all other regions. The difference in amygdala FC between post- and pre-scans was then calculated, followed by a two-sample t-test comparing the active and shame groups.
Results:
The results revealed that compared to the sham group, the active LIT group exhibited increased amygdala connectivity (Fig.1). The left amygdala showed increased FC with the left caudal-middle frontal (t=3.12, p=0.012), inferior-parietal (t=2.97, p=0.021), and right temporal pole (t=5.01, p=0.00091) and transverse temporal (t=2.41, p=0.041). Similarly, the right amygdala demonstrated increased FC with the left and right caudal-middle frontal (t=3.12, p=0.012 and t=2.48, p=0.039, respectively), and left inferior-parietal (t=3.11, p=0.013) compared to sham. In addition, the right amygdala also showed increased FC with the left hippocampus (t=3.07, p=0.014) compared to sham.
·Fig.1. Left (A) and right (B) amygdala demonstrated increased functional connectivity from pre to post among the active LIT group compared to the control sham group (p<0.05 uncorrected).
Conclusions:
Our preliminary results indicate LIT induces an increase in overall amygdala connectivity to key regions in several large-scale functional brain networks; the executive function dorsal attention network (i.e., caudal-middle frontal), default mode network (DMN) (i.e., inferior-parietal), and limbic network (i.e., hippocampus and temporal pole). Further data collection to validate these results is underway. These measured changes in functional connectivity are key to providing insights leading to optimization of light therapy and improved understanding of mechanisms underlying this highly beneficial treatment.
Brain Stimulation:
Non-Invasive Stimulation Methods Other 2
Disorders of the Nervous System:
Neurodegenerative/ Late Life (eg. Parkinson’s, Alzheimer’s) 1
Modeling and Analysis Methods:
Connectivity (eg. functional, effective, structural)
Keywords:
Degenerative Disease
FUNCTIONAL MRI
HIGH FIELD MR
Plasticity
Other - Lighting intervention therapy
1|2Indicates the priority used for review
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Please indicate below if your study was a "resting state" or "task-activation” study.
Healthy subjects only or patients (note that patient studies may also involve healthy subjects):
Was this research conducted in the United States?
Are you Internal Review Board (IRB) certified? Please note: Failure to have IRB, if applicable will lead to automatic rejection of abstract.
Were any human subjects research approved by the relevant Institutional Review Board or ethics panel? NOTE: Any human subjects studies without IRB approval will be automatically rejected.
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Provide references using APA citation style.
Blume, C. (2019). Effects of light on human circadian rhythms, sleep and mood. Somnologie (Berl), 23(3), 147-156.
Desikan, R. S. (2006). An automated labeling system for subdividing the human cerebral cortex on MRI scans into gyral based regions of interest. NeuroImage, 31(3), 968-980.
Figueiro, M. G. (2014). Tailored lighting intervention improves measures of sleep, depression, and agitation in persons with Alzheimer's disease and related dementia living in long-term care facilities. Clin Interv Aging, 9, 1527-1537.
Figueiro, M. G. (2020). Long-Term, All-Day Exposure to Circadian-Effective Light Improves Sleep, Mood, and Behavior in Persons with Dementia. J Alzheimers Dis Rep, 4(1), 297-312.
Killgore, W. D. S. (2022). Treatment with morning blue light increases left amygdala volume and sleep duration among individuals with posttraumatic stress disorder. Frontiers in Behavioral Neuroscience, 16.
Kundu, P. (2012). Differentiating BOLD and non-BOLD signals in fMRI time series using multi-echo EPI. NeuroImage, 60(3), 1759-1770.