Classification of columnar and salt-and-pepper organization in mammalian visual cortex

Abstract

<jats:p>In mammalian visual cortex, neural tuning to stimulus orientation is organized in either columnar<jats:sup>1</jats:sup> or salt- and-pepper<jats:sup>2</jats:sup> patterns across species. This is often considered to reflect disparate mechanisms of cortical development across mammalian taxa. However, it is unknown whether different cortical architectures are generated by species-specific mechanisms<jats:sup>3,4</jats:sup>, or simply originate from the variation of biological parameters within a universal principle of development<jats:sup>5–8</jats:sup>. We analysed neural parameters in eight mammalian species and found that cortical organization is predictable by a single factor: the retino-cortical mapping ratio. We show that a Nyquist sampling model explains parametric division of the patterns with high accuracy and that simulations of controlled mapping conditions reproduce both types of organization. Our results explain the origin of distinct cortical circuits under a universal development process.</jats:p>

A unifying framework for synaptic organization on cortical dendrites

“…A single parameter, the cortical magnification factor of visual space, which is generally large for animals with large cortices and small for animals with small cortices, could explain local functional clustering for orientation in ferret vs. receptive field overlap and visual space in mouse cortex (6,7,10) . Interestingly, this magnification factor is also linked to the degree of input heterogeneity which can explain the population-level (columnar vs. salt-and-pepper) organization in the ferret vs. mouse visual cortex (56) , indicating that differences in the organization of dendritic synapses might result from the same universal developmental process modulated by evolutionary variations of cortex size. Our model also generates global organization of synaptic input feature selectivity mediated by an attenuating somatic signal.…”

“…6A). The parameter p is inversely related to the cortical magnification factor of visual space, since a larger cortical magnification results in a smaller spread of receptive field centers of the synaptic inputs for any given neuron (6,7,56) (Fig. 6A).…”

Exploring pattern recognition: what is the relationship between the recognition of words, faces and other objects?

“…This research fits with the many-to-many theory of object recognition (MTM; Behrmann and Plaut 2013 ). This theory proposes that, while there may be brain regions ideally suited to the processing of certain properties of visual stimuli (see also Arcaro et al, 2019 ; Jang et al, 2019 ), these regions represent multiple object classes that share similar perceptual features. However, the MTM theory cannot explain dissociations in recognition abilities between different object domains.…”