What Geometric Visual Hallucinations Tell Us about the Visual Cortex
Neural Computation March 1, 2002 Paul C. Bressloff, Jack D. Cowan, Martin Golubitsky et al. 292 citations
Geometric visual hallucinations—tunnels, spirals, lattices, and cobwebs—are seen under psychedelics, flickering lights, or during sleep transitions. These patterns appear in both eyes and move with them, indicating a brain origin. A theory explains them as arising in the primary visual cortex (V1), modeled as a lattice of interconnected hypercolumns. The lateral connections between hypercolumns are assumed to have symmetries under the Euclidean group E(2). When V1's uniform resting state becomes unstable, spontaneous activity patterns emerge that, when mapped back to the visual field, correspond to the hallucination forms. The results depend on the connectivity details and suggest that the same cortical mechanisms process edges, contours, surfaces, and textures.