Blakemore and Campbell (1969) showed, psychophysically, that there were spatial frequency and orientation tuned mechanisms in human vision. Some neurons’ receptive fields in primate visual cortex are selective for orientation and spatial frequency and are hypothesized to underlie the psychophysically defined channels. We have measured receptive field properties – including orientation and direction selectivity, spatial and temporal tuning, contrast sensitivity, selectivity for colour and extra-classical receptive field suppression – from a large population of V1 neurons within individual cortical layers. Multidimensional analysis of tuning properties within individual layers uncovers different subpopulations, both within and between layers. Additional functional and anatomical studies have been undertaken to further elucidate the wiring within the local circuits that is related to the tuning properties and response modulation of the different subpopulations. The results provide the fabric for the development of multidimensional models of receptive field properties within the cortical circuit, thereby extending the connection between psychophysically defined channels and the underlying cortical wiring and circuits.