Researchers provide a description of the overall functional organization of the brain in three spatio-temporal patterns
UCLA researchers and colleagues at Emory University and other research centers have combined data simulation and experimental observation to bridge a gap between two major properties of the large-scale organization of the human brain – stationary and itinerant activity waves.
Functional magnetic resonance imaging suggests that the brain has a globally coherent spatial structure, but there is still no consensus among scientists on the correct way to catalog this structure. We show that a small number of spatio-temporal models can do the trick.”
Lucina Uddin, professor of psychiatry and biobehavioral sciences and director of the Brain Connectivity and Cognition Laboratory at UCLA Semel Institute for Neuroscience and Human Behavior
Taylor Bolt, the lab statistician and the study’s first author, said: “We have shown that a wide range of previously observed empirical phenomena are manifestations of three main spatio-temporal patterns.”
The study focuses on spontaneous low-frequency fluctuations dependent on blood oxygenation level (BOLD), a phenomenon discovered in the 1990s. Spontaneous fluctuations have been subjected to increasingly complex analytical techniques, leading to a vast landscape of competing descriptions of large-scale functional brain organization. Some researchers have highlighted the simultaneous synchrony of brain regions through the cortex – what the authors call a “steady” or “stationary” wave pattern. Other researchers have highlighted the temporal synchronization of brain regions through the cortex – what the authors call a “propagating” or “travelling” wave structure. There have been “few attempts to synthesize results from different approaches,” the researchers said.
Uddin compared the lack of consensus to the Indian parable of the blind men and the elephant, where each man encounters a part of the animal and comes up with a different description from all the others. “The parable teaches us the dangers of missing the ‘big picture’ due to our own limited observations,” she said.
Assuming that standing and traveling wave representations “of the brain’s intrinsic functional organization capture different aspects of a small number of spatiotemporal patterns”, the authors found that a range of previous observations could be unified. in a framework that models both the standing and traveling wave structure. The researchers said their findings provide a “description of overall functional brain organization that may inspire new hypotheses about the mechanisms underlying the coordination of activity in the brain.”
Uddin and Jason Nomi, an assistant researcher at the UCLA Semel Institute for Neuroscience and Human Behaviour, collaborated on the study with an international team including lead author Shella Keilholz, from Emory University in the US; Dr. Danilo Bzdok, from McGill University in Canada; Jorge Salas and Catie Chang, from Vanderbilt University in the United States; and Thomas Yeo of the National University of Singapore. The study was published in the July 28, 2022 issue of Natural neuroscience.
University of California – Los Angeles Health Sciences
Bolt, T., et al. (2022) A parsimonious description of the global functional organization of the brain in three spatio-temporal models. Natural neuroscience. doi.org/10.1038/s41593-022-01118-1.