Evolution of Pallial Areas and Networks Involved in Sociality: Comparison Between Mammals and Sauropsids

Abstract

Birds are extremely interesting animals for studying the neurobiological basis of cognition and its evolution. They include species that are highly social and show high cognitive capabilities. Moreover, birds rely more on visual and auditory cues than on olfaction for social behavior and cognition, just like primates. In primates, there are two major brain networks associated to sociality: (1) one related to perception and decision-making, involving the pallial amygdala (with the basolateral complex as a major component), the temporal and temporoparietal neocortex, and the orbitofrontal cortex; (2) another one related to affiliation, including the medial extended amygdala, the ventromedial prefrontal and anterior cingulate cortices, the ventromedial striatum (largely nucleus accumbens), and the ventromedial hypothalamus. In this account, we used an evolutionary developmental neurobiology approach, in combination with published comparative connectivity and functional data, to identify areas and functional networks in the sauropsidian brain comparable to those of mammals that are related to decision-making and affiliation. Both in mammals and sauropsids, there is an important interaction between these networks by way of cross projections between areas of both systems.

Topological atlas of the hypothalamus in adult rhesus monkey

“…Moreover, the pattern and strength of hypothalamic projections varies systematically from the least differentiated limbic areas to the most laminated (eulaminate) prefrontal areas (Rempel-Clower and Barbas 1998), consistent with the rules of the structural model (Barbas and Rempel-Clower 1997), which has been traced to the development and evolution of the cortex (Dombrowski et al 2001;Barbas 2015;Barbas and García-Cabezas 2016;. A recent study also predicted the common developmental origin of connected pallial and subpallial brain regions across mammalian species (Medina et al 2019). This evidence provides a clear convergence of the prosomeric model and the structural model to predict that the specificity of cortico-hypothalamic connections has a common developmental sequence that likely begins with the specification of the hypothalamus.…”

Comparative Analysis of Brain Stiffness Among Amniotes Using Glyoxal Fixation and Atomic Force Microscopy

“…Second, we applied glyoxal fixation to several amniotes to investigate the stiffness of their pallia exhibiting different morphologies. We chose representative species based on phylogenetic and histological reasons ( Puelles et al, 2000 , 2016 , 2019 ; de Juan Romero and Borrell, 2015 ; Medina et al, 2017 , 2019 ; Desfilis et al, 2018 ; Pessoa et al, 2019 ; García-Moreno and Molnár, 2020 ). We successfully obtained species-specific stiffness profiles using chick, songbird, turtle, mouse, and ferret brains, which are classified as birds, reptiles, and mammals.…”

A novel telencephalon‐opto‐hypothalamic morphogenetic domain coexpressing Foxg1 and Otp produces most of the glutamatergic neurons of the medial extended amygdala

“…The medial amygdala and medial part of the bed nucleus of the stria terminalis (BSTM) form part of a cellular continuum of the ventral telencephalon, known as the “medial extended amygdala” (Alheid & Heimer, 1988; de Olmos et al, 2004), which plays a critical role in social cognition and control of socio‐sexual behaviors (Bickart et al, 2014; Choi et al, 2005; Martínez‐García et al, 2002, 2007; Medina, Abellán, Vicario, et al, 2017a; Medina et al, 2011, 2019; Pessoa et al, 2019; Phelps & LeDoux, 2005; Swanson & Petrovich, 1998). Although located in the ventral telencephalon, these nuclei contain not only abundant GABAergic neurons (as typical of the subpallium; Swanson & Petrovich, 1998; McDonald, 2003) but also an important population of glutamatergic neurons (Choi et al, 2005).…”