The laminar organization of the motor cortex in monodactylous mammals: a comparative assessment based on horse, chimpanzee, and macaque

Abstract

The architecture of the neocortex classically consists of six layers, based on cytological criteria and on the layout of intra/interlaminar connections. Yet, the comparison of cortical cytoarchitectonic features across different species proves overwhelmingly difficult, due to the lack of a reliable model to analyze the connection patterns of neuronal ensembles forming the different layers. We first defined a set of suitable morphometric cell features, obtained in digitized Nissl-stained sections of the motor cortex of the horse, chimpanzee, and crab-eating macaque. We then modeled them using a quite general non-parametric data representation model, showing that the assessment of neuronal cell complexity (i.e., how a given cell differs from its neighbors) can be performed using a suitable measure of statistical dispersion such as the mean absolute deviation-mean absolute deviation (MAD). Along with the non-parametric combination and permutation methodology, application of MAD allowed not only to estimate, but also to compare and rank the motor cortical complexity across different species. As to the instances presented in this paper, we show that the pyramidal layers of the motor cortex of the horse are far more irregular than those of primates. This feature could be related to the different organizations of the motor system in monodactylous mammals.

The catecholaminergic innervation of the claustrum of the pig

“…We also emphasize that extrapyramidal motor pathways, and generators of motor schemes in the brainstem with all their reciprocal prosencephalic connections, have a great importance in hoofed animals, including Perissodactyla and terrestrial Cetartiodactyla (such as the pig) (for a recent description see Cozzi et al. ).…”

Reliability of fNIRS for noninvasive monitoring of brain function and emotion in sheep

“…Movement is in fact a complex task involving multiple regions of the brain 43 ; for a review of the organization of the motor cortex in large herbivores and extended references see Ref. 44 . Therefore, in our work when the sheep were moving, the specific working mechanism in the brain and the response of multiple brain areas could not be studied in detail and need to be further investigated.…”

Mapping of the Early Intrauterine Morphogenesis in the Alpaca (Vicugna pacos): External Features and Development of the Cephalic Vesicle in Comparison with the Progressive Carnegie Scale

“…The more advanced specimens, already within the definition of fetuses, showed a five‐layer stratification in the walls of the telencephalic vesicle. This stratification reflects the process of differentiation and migration of the germinal neuroepithelium cells that will eventually form the cortical columns of the neocortex (Gilbert, ), here organized in five layers as typical of large herbivores (Cozzi et al, ; van Kann et al, ). However, here we note that adult Cetartiodactyla and Perissodactyla, contrarily to rodents and primates, are generally considered to be endowed with a five‐layered cortex, for further discussion see (Cozzi et al, , ).…”