Callosal connections (CC) in early sensory areas are believed to act as conditional drivers because their impact depends on all other inputs reaching their contralateral targets for a given task. In the intact cat brain, CC to the 17/18-transition zone (TZ) act mainly as modulators, rarely as direct drivers, depending on both target and stimulus properties. Given that preferred spatial frequency (SF) gradually changes from area 17 towards 18 we suspected CC to reflect the ratio of x- and y- cell driven retinogeniculate-cortical inputs. We thus recorded monocular and binocular responses to different SFs in TZ (159 single units) and adjacent areas 17 (57) and 18 (90) while reversibly deactivating contralateral homologues.Deactivation affected all firing rates, in particular ipsilateral eye driven TZ-, and, contralateral eye driven area 18 responses. Additionally, we observed a significant interaction between SF, stimulated eye, and cortical area, with lower SF (0.15 cyc/deg) decreasing rates by 54% more than higher SF (0.6 cyc/deg) during ipsilateral eye stimulation in TZ and during contralateral eye stimulation in area 18 (48%). We simulate that CC collect probabilistically, from larger temporal (ipsi eye) than nasal hemifield (contra eye) portions, and further reproduce the cortical representation of the X-Y ratio’s decrease towards the retinal periphery. Our results suggest an incorporation of SF in the functional biases of visual CC, in combination with orientation and direction preference. These findings align with the concept of CC conditioning their impact dynamically on retinogeniculate-cortical drive and the intrinsic functional topography at contralateral targets.