Functional periodic intracortical couplings induced by
structured lateral inhibition in a linear cortical network.

Silvio P. Sabatini  and Giacomo M. Bisio
DIBE - University of Genoa, Via Opera Pia 11a, 16145 Genova, ITALY
Luigi Raffo
DIEE - University of Cagliari, Piazza d'Armi, 09123 Cagliari, ITALY

The spatial organization of cortical axon and dendritic fields could be an
interesting structural paradigm to obtain a functional specificity without
postulating highly specific feedforward connections. In this paper, we
investigate the functional implications of recurrent intracortical
inhibition when it occurs through clustered medium-range interconnection
schemes (Worgotter and Koch, 1991; Somogyi, 1989; Kritzer et al., 1992).
Moreover, the interaction between the inhibitory schemes and visual
orientation maps are explored. Assuming linearity, we show that clustered
inhibitory mechanisms can trigger a propagation process that allows the
development of extra (i.e., induced) interactions amongthe cortical sites
involved in the recurrent loops. In addition, we point out how these
interactions functionally modify the response of cortical simple cells
and yield to highly structured Gabor-likereceptive fields.
It is worthy to note that the present study should be considered not as a
realistic biological model of primary visual cortex, but as an attempt to
enucleate possible computational principles related to intracortical
connectivity and to the underlying single-cell properties.