Summary: Researchers report that the cerebral cortex can self-organize during early development, converting disordered inputs into regular, large-scale activity patterns. This process follows mathematical principles seen in other natural systems, and disturbances to these patterns could alter sensory processing and contribute to neurodevelopmental conditions such as autism.
Key Facts:
- The developing cortex can generate organized neural activity from unstructured inputs.
- Pattern formation appears to follow general mathematical rules found across nature.
- Alterations in these self-organizing processes may affect sensory perception and are implicated in neurodevelopmental disorders.
Source: University of Minnesota
Published in Nature Communications — an international team from the University of Minnesota and the Frankfurt Institute for Advanced Studies investigated how modular and ordered patterns of neural activity emerge in immature cortical networks.
The study demonstrates that the cortex itself can transform uniform or noisy inputs into structured patterns of activity, indicating intrinsic self-organization during development rather than strict imprinting from external sources.
“This transformation appears to arise within the cortical network itself, meaning the developing brain can organize its own activity,” said Gordon Smith, PhD, an assistant professor at the U of M Medical School. He noted that small-scale interactions among neurons can scale up to shape large-scale cortical organization.
According to the team, even modest changes to these local interactions—such as shifts in the balance between excitation and inhibition—could substantially alter cortical function. Such changes may influence how sensory inputs are represented and could contribute to atypical development in conditions like autism.
Combining theoretical models and experiments, the researchers found that the emergence of cortical patterns follows mathematical principles similar to those that generate patterns in other biological and physical systems, including animal coat markings and sand dune spacing. These universal rules help explain why cortical activity organizes into modular patterns with a characteristic spatial scale.
“Our data support a longstanding theoretical idea that cortical patterning during early development is driven by feedback loops balancing local excitation and lateral inhibition,” said Matthias Kaschube, PhD, professor at the Frankfurt Institute for Advanced Studies and co-investigator on the project. This LE/LI (local excitation / lateral inhibition) mechanism provides a compact explanation for how diverse, repeating activity motifs can self-assemble in the immature cortex.
The team used advanced optical methods developed at the University of Minnesota—combining widefield calcium imaging and optogenetics—to measure and manipulate activity in juvenile ferret cortex before eye opening. These approaches allowed the researchers to show that cortical networks convert uniform stimulation into a range of modular activity patterns with a preferred wavelength. When optogenetic stimulation matched that wavelength, it biased the resulting pattern; when stimulation varied in scale, the network activity shifted toward its intrinsic pattern, revealing a dynamic interplay between external input and the cortex’s built-in tendencies.
These findings indicate that early spontaneous activity and responses to uniform stimulation share a common structural organization. That overlap suggests a shared mechanism underlying the initial formation of orderly columnar maps that later support sensory representations such as orientation selectivity in visual cortex.
Ongoing work aims to determine how deviations in these self-organized activity patterns early in development affect sensory processing and behavior later in life, with implications for understanding developmental disorders and for designing interventions that support healthy cortical maturation.
Funding: Support for this research came from the National Eye Institute (grant R01EY030893-01), the Whitehall Foundation (2018-05-57), the National Science Foundation (IIS-2011542), and the German Federal Ministry of Education and Research (BMBF 01GQ2002).
About this neurodevelopment research news
Author: Alexandra Smith
Source: University of Minnesota
Contact: Alexandra Smith – University of Minnesota
Image: The image is credited to Neuroscience News
Original Research: Open access. “Self-organization of modular activity in immature cortical networks” by Gordon Smith et al., published in Nature Communications. The paper reports experimental tests of LE/LI predictions using widefield calcium imaging and optogenetic stimulation in juvenile ferret cortex, demonstrating how uniform inputs are transformed into modular patterns that reflect the network’s intrinsic spatial wavelength.
Abstract
Self-organization of modular activity in immature cortical networks
During development, cortical activity organizes into distributed modular patterns that precede the mature columnar functional architecture. Theoretical work predicts that such structure can arise dynamically from local synaptic interactions in a recurrent network characterized by effective local excitation and lateral inhibition (LE/LI).
Using simultaneous widefield calcium imaging and optogenetics in juvenile ferret cortex prior to eye opening, the study tests critical predictions of the LE/LI mechanism. The results show that cortical networks transform uniform stimulation into diverse modular patterns with a characteristic spatial wavelength. Patterned optogenetic stimulation matched to this wavelength biases evoked activity, while stimulation at different scales drives activity toward the network’s intrinsic wavelength, revealing a dynamic compromise between input drive and intrinsic organization.
Furthermore, the spatial structure of early spontaneous cortical activity — which is reflected in developing representations of visual orientation — strongly overlaps with that of uniform opto-evoked activity, supporting a shared underlying mechanism for the emergence of orderly columnar maps that underlie sensory representations in the brain.