Notes

Hubel, David H., and Torsten N. Wiesel. "Receptive fields, binocular interaction and functional architecture in the cat's visual cortex." The Journal of physiology 160.1 (1962): 106.

A great variety of neuronal cells and interconnections populate the visual cortex of mammals. Our study investigates the organization of these neurons involved in processing visual stimuli. In our previous work (Hubel & Wiesel, 1959), we described receptive fields of single cortical cells, observing responses to spots of light shone on one or both retinas. Here, we expand our previous findings by studying the visual cortex of anaesthetized cats through extracellular recordings of single cells. In particular, we examined simple receptive field responses to stimuli of different shapes, positions and orientations to highlight the spatial distribution of excitatory and inhibitory regions. We shed light on a more complex type of receptive fields which share orientation selectivity with simple cells. Complex receptive fields differ from simple ones as the response to light could not be predicted from the arrangements of excitatory and inhibitory regions. We investigated cortical cells to understand binocular influence, which allowed us to cluster cells based on ocular dominance and understand binocular interaction effects. Finally, we observed the functional architecture of the visual cortex. To do so, we exploited three techniques: comparison of the responses of cells recorded in sequence, observation of unresolved background activity and comparison of multiple recordings. Such methodologies evidenced an organization into discrete cortex columns, where each column is composed of cells that share the same receptive-field axis orientation. To conclude, we introduced a model that describes different levels in a hierarchy of visual cortex cells, where simple cells represent an early organizational stage that projects on higher-order complex cells.