Coordinated Representational Drift Across the Mouse Cortex

Area of Science:

• Neuroscience
• Systems Neuroscience
• Computational Neuroscience

Background:

• Cortical neurons exhibit dynamic spatial tuning, but coordination of this representational drift across brain regions is poorly understood.
• Understanding network-level coordination is crucial for deciphering how the brain maintains stable representations despite continuous neural changes.

Purpose of the Study:

• To investigate the coordination of representational drift across distributed cortical areas.
• To determine if spatial map geometry is preserved during neural representational drift.

Main Methods:

• Chronic widefield calcium imaging with cellular resolution in mice over 47 days.
• Tracking over 110,000 neurons across retrosplenial, visual, somatosensory, and motor cortices.
• Analyzing population activity, functional coupling, and representational drift dynamics.

Main Results:

• Spatial tuning showed a posterior-to-anterior gradient, with highest tuning in retrosplenial and visual cortices.
• All four cortical regions exhibited coordinated representational drift with similar decorrelation timescales.
• Drift preserved the geometric structure of spatial representations, consistent with an orthogonal transformation of the population code.

Conclusions:

• Representational drift is coordinated across the dorsal cortex, not independent.
• The brain maintains a stable spatial map geometry despite continuous changes in single-neuron tuning.
• This coordinated drift mechanism ensures the robustness of spatial representations during learning and experience.