Related Experiment Video
Updated: Jun 14, 2026
06:18
In Vivo Visualization of Spontaneous Activity in Neonatal Mouse Sensory Cortex at a Single-Neuron Resolution
Published on: November 21, 2023
"Slow activity transients" in infant rat visual cortex: a spreading synchronous oscillation patterned by retinal
Matthew T Colonnese1, Rustem Khazipov
1Institut de Neurobiology de la Méditérannée, Inserm, Unité 901, 13273 Marseille cedex 09, France. colonnese@inmed.univ-mrs.fr
Summary
Slow activity transients (SATs) are key in preterm infant EEG. In infant rats, these events synchronize visual cortex activity, driven by retinal waves and thalamocortical circuits, suggesting a role in visual system development.
Area of Science:
- Neuroscience
- Developmental Neuroscience
- Computational Neuroscience
Background:
- Preterm infant EEG shows infra-slow potentials with rapid oscillations, termed slow activity transients (SATs).
- The generative mechanisms and animal models for SATs remain largely unknown.
- Early cortical activity is crucial for the development of sensory circuits.
Purpose of the Study:
- To investigate the existence and characteristics of SATs in a mammalian model before eye opening.
- To elucidate the underlying mechanisms and functional significance of SATs in early visual cortex development.
- To determine the relationship between SATs and peripheral sensory input, specifically retinal waves.
Main Methods:
- In vivo electrophysiological recordings (direct-current, multisite extracellular, whole-cell) in infant rats.
- Analysis of local-field potentials and neuronal firing patterns.
- Surgical manipulation (enucleation) to assess the role of visual input.
- Comparison with in vitro recordings of retinal waves.
Main Results:
- Regularly repeating SATs were identified in the visual cortex of infant rats (postnatal day 10-11) in the absence of anesthesia.
- SATs are long-duration events (>1 mV negative LFP) comprising rapid oscillations (15-30 Hz) that synchronize 87% of neuronal activity.
- Enucleation abolished SATs, and their properties closely matched retinal waves, suggesting a retinal origin for the slow component.
- SATs spread horizontally in the cortex, synchronizing activity via rapid oscillations, and differ from ongoing cortical activity.
Conclusions:
- Early cortical activity in vivo is primarily shaped by peripheral inputs (retinal waves) and thalamocortical circuitry.
- Retinal waves provide excitatory input, which is transformed into beta oscillations by thalamocortical circuits.
- The synchronous oscillations within SATs are proposed to play a critical role in the formation of visual circuitry.
