Cell-Type-Specific Thalamocortical Inputs Constrain Direction Map Formation in Visual Cortex

Abstract

Summary: Finding the relationship between individual cognitive functions and cell-type-specific neuronal circuits is a central topic in neuroscience. In cats, the lateral geniculate nucleus (LGN) contains several cell types carrying spatially and temporally precise visual information. Whereas LGN cell types lack selectivity for motion direction, neurons in the primary visual cortex (area 17) exhibit sharp direction selectivity. Whether and how such de novo formation of direction selectivity depends on LGN cell types remains unknown. Here, we addressed this question using in vivo two-photon calcium imaging in cat area 17, which consists of two compartments receiving different combinations of inputs from the LGN cell types. The direction map in area 17 showed unique fragmented organization and was present only in small and distributed cortical domains. Moreover, direction-selective domains preferentially localized in specific compartments receiving Y and W inputs carrying low spatial frequency visual information, indicating that cell-type-specific thalamocortical projections constrain the formation of direction selectivity. : Nishiyama et al. find fragmented organization of direction columns in the cat primary visual cortex. The direction columns are predominantly located in cortical domains preferring low spatial frequency. The results suggest that cell-type-specific thalamocortical projections from LGN may constrain direction column formation in the cat visual cortex. Keywords: brain mapping, in vivo two-photon imaging, functional columns, direction selectivity, thalamus, visual cortex, thalamocortical circuit