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Carlucci, M.

Publications and source records attributed to Carlucci, M..

2 recordsLinked to original sources

Oscillation detection with period uncertainty and a limited sampling budget

Equally spaced temporal sampling is the standard protocol for the study of biological rhythms. These equispaced designs perform well when calibrated to an oscillators period yet can have systematic detection biases when applied to rhythms of unknown periodicity. Here, we present a broadly-applicable set of computational methods for seeking optimal measurement schedules for rhythm detection. Our PowerCHORD methods generate experimental designs by maximizing a closed-form expression for the statistical power of the cosinor model using a black-box optimization method (differential evolution), a brute-force search, or mixed-integer conic programming. Application of these three methods showed numerically that they improve upon equispaced designs under many experimental contexts. Our numerical results also revealed an intuitive approach for achieving optimal power for simultaneous investigation of circadian, circalunar, and circannual rhythms. Our findings suggest that timing optimization is an effective yet under-explored tool for improving biological rhythm discovery.

bioinformatics↗

Repeated MRI scans of the human brain: diurnal oscillations in healthy adults and bipolar disorder patients

Regulation of biological processes according to a 24-hr rhythm is essential for the normal functioning of an organism. Temporal variation in brain MRI data has often been attributed to circadian or diurnal oscillations; however, it is not clear if such oscillations exist. We provide the first evidence that diurnal oscillations indeed govern multiple MRI metrics. We recorded cerebral blood flow, diffusion-tensor metrics, T1 relaxation, and cortical structural features every three hours over a 24-hr period in each of 16 male controls and eight male bipolar disorder patients. Diurnal oscillations were detected in numerous MRI metrics at the whole-brain level, and regionally. Rhythmicity parameters in the bipolar disorder patients were similar to the controls for most metrics, except for a larger phase variation in cerebral blood flow. The ubiquitous nature of diurnal oscillations has broad implications for neuroimaging studies and furthers our understanding of the dynamic nature of the human brain.

neuroscience↗