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.
Meditative deconstruction—letting go of conceptual frameworks—can be modeled computationally using active inference. When an agent reduces the precision of its beliefs about hidden states at a specific hierarchical level, the phenomenology of conceptual attenuation, reduced reactivity, and shorter temporal-scale perception naturally emerges. In simulations of a facial recognition task, an agent that selects a letting-go policy when perceived affective valence becomes excessively negative can self-regulate experienced affect. The model provides a formal account of how letting go alters perception and action during meditation, offering a computational perspective on equanimity, stillness, and affect regulation.
Consciousness arises when mental contents like perceptions and thoughts are automatically identified as belonging to a specific organism. This identification is provided by a continuous flow of homeostatic feelings—sensations such as hunger, pain, well-being, or the feeling of being alive—that stem from the body's life-regulation processes. These feelings were the first conscious phenomena in evolution, selected because they gave organisms overt guidance for survival. Feelings emerge from interactions between the nervous system and nonneural body components like viscera and circulating chemicals, offering a solution to the mind-body problem by making feelings the mental version of bodily processes.