Circadian Rhythm Study
We are currently completing a brain imaging study sponsored by the National Institute of Mental Health (NIMH). In our current study, we are acquiring this imaging in people who are suffering from major depressive disorder and non-depressed participants. The study timeline is:
participants are screened to see if they meet inclusion/exclusion (e.g., they must be suffering from a certain level of depression to be in the depressed group, and they must have never suffered from depression to be in the control group).
Enrolled participants then answer a series of questions about themselves (see Participant Questionnaires below).
The participants then wear actigraphy monitors (like Fitbit) to monitor their activity and sleep. This helps us understand their baseline circadian rhythms.
The participants then come into the lab for a three night stay. On the first night, the participants sleep normally. We collect melatonin samples throughout the night to assess their circadian rhythm. On the second night, we keep the participants awake for 36 hours. Following this, the participants are once again able to sleep normally. We collect melatonin samples during the last night to determine if the 36 hours of wakefulness shifted their circadian rhythm.
After the lab stay, the participants then wear actigraphy monitors (like Fitbit) for multiple days to monitor longer term changes in their circadian rhythm.
Brain Imaging
The study involves brain imaging with Positron Emission Tomography (PET) and Magnetic Resonance Imaging (MRI).
These imaging modalities allow us to gain a lot of information about the brain, including:
PET: We can assess the density of one type of glutamate receptor (the metabotropic glutamate receptor subtype 5, mGluR5) using PET. See Figure 1 of this paper to visualize these receptors. We acquire these images three times over the course of one night to understand the circadian rhythm of these receptors.
structural MRI: Tells you the size and shape of every brain region. See an example here. (Different colors represent different brain regions.) We have automated techniques (e.g., Freesurfer) to extract volume/thickness of each region.
EEG: We use EEG during sleep to measure sleep stages before and after sleep deprivation. We also record EEG during the 36 hours of sleep deprivation.
Sleep Deprivation
Sleep deprivation can act as an antidepressant in some people and part of this study aims to understand why that is. One possibility is that people with depression have disturbed circadian rhythms (e.g., poor sleep, insomnia) and sleep deprivation "resets" these rhythms. Similarly, we want to understand who is most likely to benefit from sleep deprivation. This is why we acquire information about participants' circadian rhythms (from actigraphy and melatonin) prior to the sleep deprivation. We also acquire brain imaging to understand if the mGluR5 receptor controls this circadian rhythm.
Participant Questionnaires
Our participants complete the following surveys prior to sleep deprivation:
Adult Rejection Sensitivity Questionnaire
Childhood Trauma Questionnaire
Credibility And Expectancy Questionnaire
Edinburgh Handedness Inventory
Hamilton Depression Rating Scale (taken before, during and after sleep deprivation)
Inventory Of Depression And Anxiety
Multidimensional Scale Of Perceived Social Support
Quick Inventory Of Depressive Symptoms
Revised Social Anhedonia Scale
The following topics are currently being prepared for manuscripts by our students and interns (to give potential new interns a sense of how long it takes to complete a paper, I have included the time from joining the lab to publication for papers written by interns):
Afnan Ali (Herricks High School): Relationship between melatonin/depression and mGluR5 (joined lab as an intern in May 2023)
Piya Gupta : Relationship between actigraphy-derived circadian rhythm and melatonin-derived circadian rhythm (joined lab as an intern in February 2024)
Tzipora Guttman and Karley Ko (Staten Island Technical High School): Relationship between actigraphy-derived circadian rhythm / melatonin-derived circadian rhythm and sleep deprivation outcome (joined lab as an intern in June 2023)
Ashley Huang (Syosset High School): Prediction of antidepressant response to sleep deprivation from pretreatment activity and sleep (joined lab as an intern in May 2023)
Faheem Karim (Stony Brook University): Relationship between actigraphy-derived circadian rhythm and depression severity before and after treatment (joined lab as an intern in August 2023)
Madeena Jalili (Ward Melville High School): Relationship between mood and mGluR5 (joined lab as an intern in December 2023)
Thai Ly (Stony Brook School): Relationship between sleep disturbances and mGluR5 (joined lab as an intern in March 2023)
Jayden Neidell (Half Hollow Hills East): Relationship between sleep disturbances and mGluR5 (joined lab as an intern in January 2023)
Devika Patel (Stony Brook University): Relationship between the circadian rhythm of melatonin and the circadian rhythm of mGluR5, measured by PET (began work as VIP student in October 2022)