title: Formation of field discontinuities and islands in visual cortical maps.
abstract: The representations of visual hemifields in the extrastriate areas of various species exhibit field discontinuities and islands. We propose that these violations of retinotopy are a developmental consequence of the elongated shape of the respective cortical areas. To substantiate this claim, we investigated a model of activity-driven map formation. In agreement with observations, this model yields maps with field discontinuities if the cortical areas exceed a threshold elongation. Moreover, within the same model island representations in the periphery and the area centralis can also be understood. A multistability of the solutions in the model gives a very simple explanation for the observed interindividual variability of maps in cats. The model leads to a prediction of the radial dependence of the areal magnification factor near field discontinuities, which could be accessible for a high precision mapping experiment.
authors.affiliation: Institut für Theoretische Physik and SFB Nichtlineare Dynamik, Universität Frankfurt, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Wolf
authors.forename: H U
authors.initials: HU
authors.lastname: Bauer
authors.forename: T
authors.initials: T
authors.lastname: Geisel
mesh_terms: D000818:Animals; D002415:Cats; D003491:Cybernetics; D008953:Models, Anatomic; D008959:Models, Neurological; D014793:Visual Cortex / Q000033:anatomy & histology / Q000502:physiology*; D014794:Visual Fields / Q000502:physiology*