Cellular precision of orientation and spatial frequency maps in macaque V1

Abstract

9Functional organization of neuronal response properties along the surface of the 10 neocortex is a fundamental guiding principle of neural computation in the brain. Despite 11 this importance, the cellular precision of functional maps is still largely unknown. We 12 address the challenge by using two-photon calcium imaging to measure cell-specific 13 orientation and spatial frequency (SF) responses across fields of macaque V1 superficial 14 layers. The cellular orientation maps confirm iso-orientation domains, but rarely show 15 pinwheels. Pinwheels obtained through conventional Gaussian smoothing and vector 16 summation of orientation responses mostly overlap with blood vessel regions, 17 suggesting false singularities. Cellular SF maps clarify existing controversies by showing 18 weak iso-frequency clusters, which also suggests a weak geometric relationship between 19 orientation and SF maps. Most neurons are tuned to medium frequencies, but the tuning 20