Torus graphs for multivariate phase coupling analysis
© Institute of Mathematical Statistics, 2020. Angular measurements are often modeled as circular random variables, where there are natural circular analogues of moments, including correlation. Because a product of circles is a torus, a d-dimensional vector of circular random variables lies on a d-di...
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| Format: | Article |
| Language: | English |
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Institute of Mathematical Statistics
2021
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| Online Access: | https://hdl.handle.net/1721.1/138286 |
| _version_ | 1826192855449731072 |
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| author | Klein, Natalie Orellana, Josue Brincat, Scott L Miller, Earl K Kass, Robert E |
| author2 | Massachusetts Institute of Technology. Department of Brain and Cognitive Sciences |
| author_facet | Massachusetts Institute of Technology. Department of Brain and Cognitive Sciences Klein, Natalie Orellana, Josue Brincat, Scott L Miller, Earl K Kass, Robert E |
| author_sort | Klein, Natalie |
| collection | MIT |
| description | © Institute of Mathematical Statistics, 2020. Angular measurements are often modeled as circular random variables, where there are natural circular analogues of moments, including correlation. Because a product of circles is a torus, a d-dimensional vector of circular random variables lies on a d-dimensional torus. For such vectors we present here a class of graphical models, which we call torus graphs, based on the full exponential family with pairwise interactions. The topological distinction between a torus and Euclidean space has several important consequences. Our development was motivated by the problem of identifying phase coupling among oscillatory signals recorded from multiple electrodes in the brain: oscillatory phases across electrodes might tend to advance or recede together, indicating coordination across brain areas. The data analyzed here consisted of 24 phase angles measured repeatedly across 840 experimental trials (replications) during a memory task, where the electrodes were in 4 distinct brain regions, all known to be active while memories are being stored or retrieved. In realistic numerical simulations, we found that a standard pairwise assessment, known as phase locking value, is unable to describe multivariate phase interactions, but that torus graphs can accurately identify conditional associations. Torus graphs generalize several more restrictive approaches that have appeared in various scientific literatures, and produced intuitive results in the data we analyzed. Torus graphs thus unify multivariate analysis of circular data and present fertile territory for future research. |
| first_indexed | 2024-09-23T09:30:13Z |
| format | Article |
| id | mit-1721.1/138286 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T09:30:13Z |
| publishDate | 2021 |
| publisher | Institute of Mathematical Statistics |
| record_format | dspace |
| spelling | mit-1721.1/1382862023-07-28T20:08:28Z Torus graphs for multivariate phase coupling analysis Klein, Natalie Orellana, Josue Brincat, Scott L Miller, Earl K Kass, Robert E Massachusetts Institute of Technology. Department of Brain and Cognitive Sciences © Institute of Mathematical Statistics, 2020. Angular measurements are often modeled as circular random variables, where there are natural circular analogues of moments, including correlation. Because a product of circles is a torus, a d-dimensional vector of circular random variables lies on a d-dimensional torus. For such vectors we present here a class of graphical models, which we call torus graphs, based on the full exponential family with pairwise interactions. The topological distinction between a torus and Euclidean space has several important consequences. Our development was motivated by the problem of identifying phase coupling among oscillatory signals recorded from multiple electrodes in the brain: oscillatory phases across electrodes might tend to advance or recede together, indicating coordination across brain areas. The data analyzed here consisted of 24 phase angles measured repeatedly across 840 experimental trials (replications) during a memory task, where the electrodes were in 4 distinct brain regions, all known to be active while memories are being stored or retrieved. In realistic numerical simulations, we found that a standard pairwise assessment, known as phase locking value, is unable to describe multivariate phase interactions, but that torus graphs can accurately identify conditional associations. Torus graphs generalize several more restrictive approaches that have appeared in various scientific literatures, and produced intuitive results in the data we analyzed. Torus graphs thus unify multivariate analysis of circular data and present fertile territory for future research. 2021-12-01T19:10:47Z 2021-12-01T19:10:47Z 2020 2021-12-01T19:07:58Z Article http://purl.org/eprint/type/JournalArticle https://hdl.handle.net/1721.1/138286 Klein, Natalie, Orellana, Josue, Brincat, Scott L, Miller, Earl K and Kass, Robert E. 2020. "Torus graphs for multivariate phase coupling analysis." Annals of Applied Statistics, 14 (2). en 10.1214/19-AOAS1300 Annals of Applied Statistics Creative Commons Attribution-Noncommercial-Share Alike http://creativecommons.org/licenses/by-nc-sa/4.0/ application/pdf Institute of Mathematical Statistics arXiv |
| spellingShingle | Klein, Natalie Orellana, Josue Brincat, Scott L Miller, Earl K Kass, Robert E Torus graphs for multivariate phase coupling analysis |
| title | Torus graphs for multivariate phase coupling analysis |
| title_full | Torus graphs for multivariate phase coupling analysis |
| title_fullStr | Torus graphs for multivariate phase coupling analysis |
| title_full_unstemmed | Torus graphs for multivariate phase coupling analysis |
| title_short | Torus graphs for multivariate phase coupling analysis |
| title_sort | torus graphs for multivariate phase coupling analysis |
| url | https://hdl.handle.net/1721.1/138286 |
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