Natural scene statistics and the structure of orientation maps in the visual cortex

Abstract

Visual activity after eye-opening influences feature map structure in primary visual cortex (V1). For instance, rearing cats in an environment of stripes of one orientation yields an over-representation of that orientation in V1. However, whether such changes also affect the higher-order statistics of orientation maps is unknown. A statistical bias of orientation maps in normally raised animals is that the probability of the angular difference in orientation preference between each pair of points in the cortex depends on the angle of the line joining those points relative to a fixed but arbitrary set of axes. Natural images show an analogous statistical bias; however, whether this drives the development of comparable structure in V1 is unknown. We examined these statistics for normal, stripe-reared and dark-reared cats, and found that the biases present were not consistently related to those present in the input, or to genetic relationships. We compared these results with two computational models of orientation map development, an analytical model and a Hebbian model. The analytical model failed to reproduce the experimentally observed statistics. In the Hebbian model, while orientation difference statistics could be strongly driven by the input, statistics similar to those seen in experimental maps arose only when symmetry breaking was allowed to occur spontaneously. These results suggest that these statistical biases of orientation maps arise primarily spontaneously, rather than being governed by either input statistics or genetic mechanisms.

Online learning and stimulus-driven responses of neurons in visual cortex

“…Statistical analysis for animal's OPMs also illustrated the anisotropic features (Lee et al 2003) (see also Lee and Kardar 2006), where a high-order statistical property, the reduced symmetry (orientation difference between any pair of cells depends on their topographic relation), was reported. A recent study also provides similar findings for the cortical maps of cats (Hunt et al 2009). …”

Link between orientation and retinotopic maps in primary visual cortex

“…Namely, a set of neurons within a cortical column that share the same inputs will be biased toward the same preferred orientation. The global structure of the interference pattern accounts for the hexagonal symmetry of orientation maps (16,18) and a tendency for cocircularity in their organization (30)(31)(32)(33)(34). Altogether, the ability of the model to account for these diverse findings lends support to the notion that spatially structured and limited input from the contralateral retina may seed receptive fields and the orientation map during the earliest stages of development (9,10,(35)(36)(37)(38)(39)(40)(41)(42)(43)(44)(45)(46)(47)(48)(49)(50)(51).…”

Sparse Models for Computer Vision

“…Indeed, we based our reasoning on inferential processes such as they are reflected in the organization of neural structures. For instance, there is a link between co-circularity and the structure of orientation maps (Hunt et al, 2009). This should be included in further perspectives of these sparse models.…”