Mesoscale Mapping of Mouse Cortex Reveals Frequency-Dependent Cycling between Distinct Macroscale Functional Modules.

Area of Science:

• Neuroscience
• Systems Neuroscience
• Computational Neuroscience

Background:

• Resting-state functional connectivity mapping in mice has identified correlated activity motifs.
• The organization of these motifs into larger modules driving brain-wide activity sequences remains unclear.
• Understanding brain organization across multiple spatiotemporal scales is crucial for interpreting brain function.

Purpose of the Study:

• To explore cortical activity parcellation in awake mice using mesoscopic calcium imaging.
• To characterize the spatiotemporal organization of spontaneous cortical activity at different scales.
• To define the rules governing interactions between cortical areas.

Main Methods:

• Utilized mesoscopic calcium imaging in head-fixed, awake mice of both sexes.
• Applied spectral decomposition to analyze spontaneous cortical activity.
• Performed correlation analysis to identify clusters and principles of activity organization.

Main Results:

• Identified two dominant frequency modes (<1 Hz and ~3 Hz) with distinct spatial signatures.
• Revealed frequency-dependent cortical macro-organization principles: a rotating polymodal-association pinwheel and activity symmetry planes at low frequencies.
• Observed larger coactivated clusters and an enlarged default mode network-like region at higher frequencies (>1 Hz).

Conclusions:

• Spontaneous cortical activity exhibits frequency-dependent organization into distinct macro-architectural principles.
• These findings provide a framework for understanding functional reorganization in neurological diseases.
• The constrained structure of intra-areal cortical activity flow may be exploitable for therapeutic normalization.