Gamma oscillations provide a stable geometric scaffold for color representation in primate inferior temporal cortex

To bridge the gap between neural geometry and oscillatory dynamics, we analyzed gamma-band oscillations in macaque inferior temporal cortex using large-scale electrocorticography. We identified an "oscillatory manifold"-a stable, low-dimensional geometric structure embedded within oscillatory waveforms-that encodes color information. Within this manifold, trajectories for different colors were segregated via color-specific amplitude modulations of a shared oscillatory carrier. While the absolute spatial separation of these trajectories rapidly decayed following an initial stimulus-locked transient, their scale-invariant topological shape was conserved. Although stimulus shape was decodable from gamma-band power, it lacked the stable geometric structure observed for color. This contrast confirms that the oscillatory manifold is a specific representational format rather than a generic byproduct of neural activation. Consequently, gamma oscillations provide a dynamic "geometric scaffold" safeguarding perceptual fidelity against energy fluctuations. This framework unifies representational geometry with oscillatory dynamics, offering a feature-specific perspective on how the cortex stabilizes sensory information.