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Updated: Jun 27, 2026
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In Vivo Visualization of Spontaneous Activity in Neonatal Mouse Sensory Cortex at a Single-Neuron Resolution
Published on: November 21, 2023
Spatial and temporal scales of neuronal correlation in primary visual cortex
1Center for the Neural Basis of Cognition, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA. masmith@cnbc.cmu.edu
Summary
Cortical neuron activity shows correlations. Visual stimuli decrease this correlation, revealing distinct spatial scales and circuit mechanisms, including horizontal connections and feedback pathways, crucial for visual processing.
Area of Science:
- Neuroscience
- Computational Neuroscience
- Visual Cortex
Background:
- Cortical neuron activity exhibits correlations, including shared trial-to-trial response fluctuations and synchronous spiking.
- Understanding the mechanisms generating neural correlations is vital for deciphering their role in cortical processing.
Purpose of the Study:
- Investigate the spatial extent and functional specificity of correlated spontaneous and evoked neural activity.
- Elucidate the contributions of feedforward, recurrent, and feedback pathways to neural correlations based on their distinct properties.
Main Methods:
- Recorded single unit activity using microelectrode arrays to measure correlations across numerous neuron pairs.
- Analyzed correlations over a wide range of spatial scales to differentiate underlying circuit mechanisms.
Main Results:
- Correlated evoked activity arises from two mechanisms: one with high temporal precision and limited spatial extent (~3 mm), likely involving horizontal connections.
- A second mechanism for evoked activity correlation operates on a slow timescale, extending to at least 10 mm, suggesting feedback from extrastriate cortex.
- Spontaneous activity showed similar spatial extent but was approximately twice as strong as evoked activity.
- Visual stimuli significantly decreased neural correlation, especially at response onset.
Conclusions:
- Neural correlations in the visual cortex are shaped by distinct spatial scales and temporal dynamics, implicating specific circuit elements.
- The observed decrease in correlation upon visual stimulation suggests a dynamic modulation of network activity during sensory processing.
- These findings provide critical constraints for models of neural computation and the functional role of neural correlations in the visual system.
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