Translation-Invariant Orientation Tuning in Visual "Complex" Cells Could Derive from Intradendritic Computations

voltage-dependent dendritic ion channels. We conclude that unoriented LGN inputs to a complex cell could contribute in a significant way to its orientation tuning, acting in concert with oriented inputs to the same cell provided by simple cells or other complex cells. As such, our model provides a novel, experimentally testable hypothesis regarding the basis of orientation tuning in the complex cell population, and more generally underscores the potential importance of nonlinear intradendritic subunit processing in cortical neurophysiology. Key words: complex cells; orientation tuning; active dendrites; single neuron computation; visual cortex; energy models; computational models The mechanisms underlying orientation tuning in visual cortical neurons are among the most studied in systems neuroscience. Under the original Hubel and Wiesel (1962) classification scheme, simple cell receptive fields (RFs) could be subdivided into separable, oriented ON and OFF subregions