Summary: A new paper from researchers at MIT highlights the central role of brain rhythms in cognition. The study examines how rhythmic electric fields produced by ensembles of neurons can shape and synchronize nearby cells, creating coordinated activity that supports perception, memory, and higher cognitive functions.
By linking the microscopic level of individual neuron spikes with the macroscopic level of large-scale brain coordination, the authors propose that oscillatory electrical activity—commonly referred to as brain waves or rhythms—organizes information processing. Understanding these rhythmic dynamics, they argue, is essential for both basic neuroscience and for developing treatments that target disruptions in neural synchrony.
Key Facts:
- The study emphasizes ephaptic coupling, where an electrical field produced by active neurons influences neighboring cells, promoting alignment and synchrony across populations.
- Lower-frequency beta rhythms appear to regulate higher-frequency gamma rhythms, shaping when and where sensory information is encoded and retrieved.
- Insights about rhythm-driven coordination could inform interventions for disorders such as schizophrenia, epilepsy, and Parkinson’s disease, which involve disturbed neural synchrony.
Source: MIT
Observing a single pixel under a microscope won’t tell you what a whole video displays, and studying an isolated neuron can miss the emergent behaviors that underlie cognition. Three MIT neuroscientists—Earl Miller, Scott Brincat, and Jefferson Roy—argue that cognition arises from coordinated activity across millions of neurons and that brain rhythms are a crucial organizing principle for that coordination. In a recent review, they articulate a framework showing how oscillatory electric fields drive large-scale neural organization.
Brain rhythms were once regarded largely as epiphenomena, but Miller and colleagues contend that they play active roles in structuring neural computation. While detailed studies of synapses, circuits, and spiking patterns have advanced our knowledge, the authors emphasize the need to integrate those findings with concepts that operate at the rhythm and population levels—scales that can cover entire regions or multiple brain areas.
“Spiking and anatomy are important, but there is more going on above and beyond that,” says Earl Miller, senior author and faculty member at The Picower Institute for Learning and Memory and the Department of Brain and Cognitive Sciences at MIT. “A lot of functionality relevant to cognition is expressed at the level of coordinated rhythms.”
The stakes of studying rhythmic coordination extend beyond basic science. Many neurological and psychiatric conditions feature disruptions in emergent properties like neural synchrony. The authors stress that interpreting and interfacing with these emergent dynamics could prove essential for new, effective therapies.
The emergence of thoughts
Electric fields link single-cell activity to broad-scale coordination.
Through ephaptic coupling, the electrical field generated by active neurons can modulate the membrane voltages of nearby cells, nudging them toward alignment. In other words, electric fields both reflect and influence neural activity, creating a feedback loop that organizes ensembles of cells.
Previous work from Miller’s lab demonstrated, via experiments and computational modeling, that information encoded in population-level electric fields can often be decoded more reliably than the information carried by spikes of single neurons. Later studies indicated that rhythmic fields may coordinate memory processes across brain regions.
At larger scales, rhythmic electric fields appear to carry information between cortical layers and regions. The lab’s recordings during working memory tasks show that lower-frequency beta rhythms—often originating in deeper cortical layers—can regulate the amplitude and timing of faster gamma rhythms in more superficial layers. This hierarchical interaction allows beta to impose context and timing constraints on gamma-mediated sensory encoding.
These beta rhythms function like stencils over patches of cortex, determining where and when gamma can represent sensory items in working memory. Miller labels this concept “Spatial Computing”: beta establishes the rules and spatial-temporal patterns of a task, while gamma carries the changing content within those constraints. This mechanism supports flexible encoding and is compatible with the widely observed neural phenomenon of mixed selectivity, where single neurons contribute to multiple types of information depending on context.
The authors also describe the concept of “subspace coding.” Rather than permitting the astronomically large number of possible activity patterns from many independent neurons, rhythm-driven coordination constrains population activity to a much smaller set of structured subspaces. These subspaces both segregate and integrate information, enabling the brain to protect memories from interference and to multiplex different information streams concurrently.
Rhythmic coordination—through phase relationships and frequency bands—can amplify aligned signals or offset them to avoid interference. Such organization allows cognitive processes to emerge from collective activity and suggests that studying rhythms is vital to understanding how higher-level functions arise in the brain.
The authors conclude that while analyses of individual neurons and synapses remain indispensable, fully capturing brain complexity requires studying these elements together to identify emergent properties and relate them to cognition and disease.
About this cognition and neuroscience research news
Author: David Orenstein
Source: MIT
Contact: David Orenstein – MIT
Image: The image is credited to Neuroscience News
Original Research: Open access. “Cognition is an emergent property” by Earl Miller et al., Current Opinion in Behavioral Sciences
Abstract
Cognition is an emergent property
Cognition depends on the flexible organization of neural activity. This discussion examines how many aspects of that organization arise as emergent properties that cannot be reduced simply to individual components. We describe how electrical fields in the brain provide a rapid medium for propagating activity and how population-level activity patterns can shape computation through mechanisms such as subspace coding.