The mammalian olfactory system confronts an extraordinary computational challenge: encoding a vast, high-dimensional chemical space into a finite neural representation that supports robust odor identification, discrimination, and dynamic tracking. Prevailing models of olfactory coding largely conceptualize the initial neural representation in the olfactory bulb as a scalar map, where the spatial pattern of glomerular activation intensity corresponds to odor identity. This paper introduces the Glomerular Field Theory (GFT), a novel framework that posits a fundamental reinterpretation of this initial coding stage. GFT proposes that the olfactory bulb’s glomerular layer generates not a scalar map, but a two-dimensional vector field. Each activated glomerulus is hypothesized to encode a vector defined by two orthogonal dimensions: Activation Intensity (Magnitude), corresponding to the integrated firing rate of converging olfactory receptor neurons, and Temporal Motif (Phase), corresponding to the dominant temporal firing pattern of that same neural population. This bidimensional representation, grounded in recent physiological evidence of distinct and reliable temporal response motifs, exponentially increases the coding capacity of the olfactory bulb without requiring additional anatomical complexity. GFT provides a unifying mechanism to explain fine odor discrimination, mixture segmentation, and the processing of dynamic odor plumes. By reframing the primary olfactory code from a static intensity landscape to a dynamic vector field, this theory offers a more powerful and biophysically plausible model for understanding the fundamental principles of chemosensation and proposes new, testable hypotheses for future experimental and computational investigation.
Yıldırım, E. (2025). Glomerular Field Theory: A Bidimensional Framework for Olfactory Coding. Zenodo. https://doi.org/10.5281/zenodo.17047853
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