Ajuste de frecuencia espacial sigue la invarianza de escala en la corteza visual humana

Our visual system can recognize patterns across many spatial scales. A fundamental assumption in visual neuroscience is that this ability relies on the putative scale-invariant properties of receptive fields in early vision, whereby the spatial area over which a visual neuron responds is proportional to the spatial scale of information it can encode (i.e. spatial frequency). In other words, the resolution of spatial sampling of a receptive field is assumed to be constant in visual cortex. However, this assumption has gone untested in human visual cortex. To address this, we leveraged model-based fMRI techniques that characterize the spatial tuning and spatial frequency preferences of cortical subpopulations sampled within a voxel across eight participants (five female, three male). We find that the voxel-wise ratio between peak spatial frequency tuning and receptive field size - expressed as "cycles per receptive field" (CPF) - remains constant across visual areas V1, V2, and V3, suggesting that, at the population-level, spatial frequency preferences are inversely proportional to receptive field size, a tenet of scale invariance in early human vision.Significance Statement The human visual system interprets patterns across a range of spatial scales, a capability thought to rely on scale-invariant properties of receptive fields. Although widely assumed, this principle had not been directly tested in the human brain. Using model-based fMRI, we measured how population receptive field size and spatial frequency tuning vary across the visual field. We use a novel metric, cycles per receptive field (CPF), to reveal that spatial frequency preferences scale inversely with receptive field size across early visual areas (V1-V3). This provides the first direct evidence of scale invariance in the human visual cortex and offers a new framework for characterizing how spatial information is sampled and represented in early vision.