In a new article, a trio of MIT neuroscientists argue that thought emerges and is controlled in the brain through the coordinated activity of millions of neurons. They propose that understanding cognition and its disorders requires studying it at that level by observing how brain waves or rhythms drive neural activity. Historically dismissed as byproducts of neural activity, brain rhythms are actually critical for organizing it and understanding cognition at a higher level.
Senior author Miller, along with Brincat and Roy, emphasize the importance of studying the brain at the scale of brain rhythms, which can span individual or multiple brain regions. They suggest that spiking and anatomy are essential but only provide part of the picture of brain functionality. By studying the emergent properties of neural synchrony, researchers may gain insight into various neurological and psychiatric disorders, such as schizophrenia, epilepsy, and Parkinson’s.
The researchers point out that the coordination and organization of neural activity at a larger scale are facilitated by electric fields, which can influence the activity of neighboring neurons through ephaptic coupling. They have shown in previous studies that the information encoded in electric fields generated by ensembles of neurons can be more reliably read out than the information encoded by individual cell spikes. Additionally, rhythmic electric fields play a role in coordinating memories between brain regions.
The lab’s research has shown that beta rhythms in deeper layers of the cortex regulate the power of gamma rhythms in more superficial layers, influencing sensory information encoding and retrieval. This control is essential in cognitive processes, as beta rhythms act as stencils that pattern where and when gamma can encode sensory information into memory. This structure enables neurons to encode multiple types of information at once, known as mixed selectivity, by organizing neural responses into subspaces through brain rhythms.
The concept of subspace coding suggests that coordinated brain rhythms reduce the number of possible outcomes from neural activity by organizing it into fewer, more manageable subspaces. This coordination allows for the segregation and integration of information, ensuring that neural activity representing specific information is protected from interference. Understanding the power of brain rhythms to coordinate and organize information processing is crucial for understanding functional cognition in the brain.
Overall, the authors emphasize the importance of studying brain rhythms in addition to individual neural components to fully capture the complexity of the brain. By analyzing the emergent properties of neural activity at the scale of brain rhythms, researchers may gain a deeper understanding of cognitive processes and potentially develop effective treatments for neurological disorders. This research provides valuable insights into how thought emerges in the brain and the significance of coordination and organization in neural activity.
