Orientation selectivity in rodent primary visual cortex

GERMSN MATO

Conferencia; Brains at the crossroads of theory and experiment.; 2023

Neurons in the primary visual cortex (V1) of rodents are selective to the orientation of the stimulus, as in other mammals such as cats and monkeys. However, in contrast with those species, their neurons display a very different type of spatial organization. Instead of orientation maps they are organized in a “salt and pepper” pattern, where adjacent neurons have completely different preferred orientations. This structure has motivated both experimental and theoretical research with the objective of determining which aspects of the connectivity patterns and intrinsic neuronal responses can explain the observed behavior.Here we present a model based on random connectivity patterns and elongated receptive fields in the Lateral Geniculate Nucleus (LGN) cells.This model allows us to evaluate analytically the statistical structure of the LGN -> V1 input. We find that the input is selective to orientation but that the different components have very different behaviors, with respect to the number of feed-forward connections and the elongation of the LGN receptive fields. These results are compared with experiments where thalamic input is measured by silencing cortical activity. We also consider direction selectivity by introducing heterogeneous temporal kernels in LGN cells.