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Nkx2-1 binds to both EphB1 and EphB3 promoters in vivo and drives their expression. A , Schematic drawing of Nkx2-1 binding sites (gray and black boxes) in the EphB1 and EphB3 loci. B , ChIP assays of E13.5 subpallium using a polyclonal antibody against Nkx2-1 and a nonspecific rabbit anti-IgG (RbIgG). Input chromatin represents 1% of the total chromatin. Negative ( Ϫ , all reagents except DNA) controls were included in each run. C , Quantification of the intensity of each PCR band obtained from the ChIP assays and normalized against the input band. Graphs show average Ϯ SEM. D , Quantification of the relative luciferase activity generated by the wild-type EphB1_reg3 , EphB1_reg4 , or EphB3_reg1–2 promoter regions compared with the luciferase activity generated by the same promoter regions but with a deletion of the Nkx2-1 consensus binding sites. Graphs show average Ϯ SEM. E , Quantitative PCR analysis for EphB1 and EphB3 in cells obtained from MGEs electroporated with pCAGIG or pCAGIG ϩ Nkx2-1 . Graphs show average Ϯ SEM.
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In the developing telencephalon, the medial ganglionic eminence (MGE) generates many cortical and virtually all striatal interneurons. While the molecular mechanisms controlling the migration of interneurons to the cortex have been extensively studied, very little is known about the nature of the signals that guide interneurons to the striatum. Her...
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... and ErbB4 / ;HER4 heart mutant (F ) embryos. G, Quantification of the number of Nkx2-1-expressing cells in the caudal striatum of E15.5 control and ErbB4 / HER4 heart mutant embryos. Graphs show average SEM. H, I, Expression of Nkx2-1 in the striatum of E15. although with very high affinity to EphB1_ region 3, EphB1_region 4, and EphB3_region 2 [ Fig. 6A-C; n 3; relative intensity of PCR band normalized against the input band: 0.77 0.06 (Nkx2-1) and 0.11 0.01 (Rb IgG) for EphB1_region 4, 0.78 0.08 (Nkx2-1) and 0.16 0.02 (Rb IgG) for EphB1_region 4, 0.87 0.17 (Nkx2-1) and 0.07 0.05 (Rb IgG) for EphB3_region 2, average SEM; *p 0.05, **p 0.01, and ***p 0.001, t test]. To further confirm ...
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... 0.16 0.02 (Rb IgG) for EphB1_region 4, 0.87 0.17 (Nkx2-1) and 0.07 0.05 (Rb IgG) for EphB3_region 2, average SEM; *p 0.05, **p 0.01, and ***p 0.001, t test]. To further confirm that Nkx2-1 can acti- vate the expression of EphB1 and EphB3 we then performed luciferase assays using the promoter regions that appeared more significant in ChIP assays (Fig. 6D). For each of these regions, we performed par- allel experiments in which we compared the effect of Nkx2-1 on luciferase activity using the wild-type Nkx2-1 consensus binding sites and equivalent construc- tions in which these regions were specifi- cally deleted. We found a significant decrease in the luciferase activity in the ...
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... we compared the effect of Nkx2-1 on luciferase activity using the wild-type Nkx2-1 consensus binding sites and equivalent construc- tions in which these regions were specifi- cally deleted. We found a significant decrease in the luciferase activity in the presence of Nkx2-1 when consensus bind- ing sites were deleted for both EphB1 and EphB3 [ Fig. 6D; n 5; relative luciferase activity: 0.95 0.11 (EphB1_region 3_wt), 1.04 0.13 (EphB1_region 3_del1), 0.92 0.05 (EphB1_region 4_wt), 0.46 0.03 (EphB1_region 4_del1), 0.98 0.04 (EphB3_region 1-2_wt), 0.59 0.09 (EphB3_region 1-2_del1), 0.98 0.04 (EphB3_region 1-2_wt), and 0.51 0.13 (EphB3_region 1-2_del2), average SEM; *p 0.05, **p 0.01, ...
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... observations, we isolated RNA from MGEs electroporated with pCAGIG or pCAGIGNkx2-1 and we performed quantitative PCR. In these experiments, we confirmed a significant increase in the expression of EphB1 in Nkx2-1 overexpressing cells [n 3; mRNA fold change: 1.05 0.04 (control), 2.21 0.35 (Nkx2-1), average SEM; *p 0.05, t test], but not for EphB3 (Fig. 6E). This later result might be a consequence of the timing of the experiment or the sensitivity of our assay for this particular receptor. However, our collective re- sults suggest that Nkx2-1 directly regulates the expression of EphB receptors in striatal interneurons, which reinforce the view that EphB/ephrinB interactions control their ...
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Diverse types of glutamatergic pyramidal neurons (PyNs) mediate the myriad processing streams and output channels of the cerebral cortex, yet all derive from neural progenitors of the embryonic dorsal telencephalon. Here, we establish genetic strategies and tools for dissecting and fate mapping PyN subpopulations based on their developmental and mo...
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... However, there is still no rationale about whether alterations in the scaffold protein Cntnap2 can lead to migration abnormalities in these interneurons (Rapanelli et al., 2017b). Striatal cell migration is tightly regulated (Villar-Cervino et al., 2015), and genetic and environmental factors that perturb cell migration and distribution result in improper cell positioning, and E/I imbalances in ASD (Guo and Anton, 2014;de la Torre-Ubieta et al., 2016). There are reciprocal mechanisms at play in the developing brain, whereby interneuron migration influences principal cell generation (Silva et al., 2018), and activity of the principal cells affects interneuron cell survival (Wong et al., 2018). ...
Interneurons are fundamental cells for maintaining the excitation-inhibition balance in the brain in health and disease. While interneurons have been shown to play a key role in the pathophysiology of autism spectrum disorder (ASD) in adult mice, little is known about how their maturation is altered in the developing striatum in ASD. Here, we aimed to track striatal developing interneurons and elucidate the molecular and physiological alterations in the Cntnap2 knockout mouse model. Using Stereo-seq and single-cell RNA sequencing data, we first characterized the pattern of expression of Cntnap2 in the adult brain and at embryonic stages in the medial ganglionic eminence (MGE), a transitory structure producing most cortical and striatal interneurons. We found that Cntnap2 is enriched in the striatum, compared to the cortex, particularly in the developing striatal cholinergic interneurons. We then revealed enhanced MGE-derived cell proliferation, followed by increased cell loss during the canonical window of developmental cell death in the Cntnap2 knockout mice. We uncovered specific cellular and molecular alterations in the developing Lhx6-expressing cholinergic interneurons of the striatum, which impacts interneuron firing properties during the first postnatal week. Overall, our work unveils some of the mechanisms underlying the shift in the developmental trajectory of striatal interneurons which greatly contribute to the ASD pathogenesis.
... Previous studies have identified genes responsible for various characteristics of MGE lineage neurons. These include specification of MGE ventricular progenitors by sustained expression of Nkx2-1 64,65 , the regulation of PV cortical interneuron migration by Sp8/Sp9 66 , the differentiation and maturation of SST cortical interneurons by Satb1 67 , and the allocation of MGE lineage striatal neurons via chemoattractive and chemorepulsive cues in response to Nrg1/ErbB4 and EphB/ephrinB signaling, respectively 68 . However, to our knowledge, St18 is the first transcription factor identified in the vertebrate brain that directs progenitor cells to delineate between projection neuron over interneuron identity. ...
The medial ganglionic eminence (MGE) produces both locally-projecting interneurons, which migrate long distances to structures such as the cortex as well as projection neurons that occupy subcortical nuclei. Little is known about what regulates the migratory behavior and axonal projections of these two broad classes of neurons. We find that St18 regulates the migration and morphology of MGE neurons in vitro. Further, genetic loss-of-function of St18 in mice reveals a reduction in projection neurons of the globus pallidus pars externa. St18 functions by influencing cell fate in MGE lineages as we observe a large expansion of nascent cortical interneurons at the expense of putative GPe neurons in St18 null embryos. Downstream of St18, we identified Cbx7, a component of Polycomb repressor complex 1, and find that it is essential for projection neuron-like migration but not morphology. Thus, we identify St18 as a key regulator of projection neuron vs. interneuron identity. The medial ganglionic eminence produces both interneurons and projection neurons, though how this fate choice is made is not well established. Here they show that St18 regulates migration and morphology of MGE neurons, inducing projection neuron fates.
... Most GABAergic interneurons populating the telencephalon (i.e. the hippocampus, cortex and striatum) share a common developmental origin [22][23][24][25]. Accordingly, these interneurons tend to diversify into a handful of major classes with recognizable morphology, electrophysiology, and molecular expression [26][27][28][29][30][31][32][33]. ...
... For recording performed in the primary somatosensory cortex, juvenile C57BL/6 mice (Janvier) aged P14-P17 were deeply anesthetized with halothane and decapitated. Brains were quickly removed and cut into 300 μm thick slices with a 30-40˚inclination from the sagittal plane into an ice-cold slicing solution containing (in mM): choline chloride (110), sodium ascorbate (11.6), MgCl2 (7), KCl (2.5), NaH2PO4 (1.25), glucose (25), NaHCO3 (25), and sodium pyruvate (3.1). Slices were maintained at room temperature until use in a holding chamber containing artificial cerebrospinal fluid (aCSF) containing (in mM): CaCl2 (2), KCl (2.5), MgCl2 (1), NaH2PO4 (1.25), NaCl (126), glucose (20), NaHCO3 (26) and kynurenic acid (1). ...
... For recording performed in the primary somatosensory cortex, juvenile C57BL/6 mice (Janvier) aged P14-P17 were deeply anesthetized with halothane and decapitated. Brains were quickly removed and cut into 300 μm thick slices with a 30-40˚inclination from the sagittal plane into an ice-cold slicing solution containing (in mM): choline chloride (110), sodium ascorbate (11.6), MgCl2 (7), KCl (2.5), NaH2PO4 (1.25), glucose (25), NaHCO3 (25), and sodium pyruvate (3.1). Slices were maintained at room temperature until use in a holding chamber containing artificial cerebrospinal fluid (aCSF) containing (in mM): CaCl2 (2), KCl (2.5), MgCl2 (1), NaH2PO4 (1.25), NaCl (126), glucose (20), NaHCO3 (26) and kynurenic acid (1). ...
GABAergic interneurons tend to diversify into similar classes across telencephalic regions. However, it remains unclear whether the electrophysiological and molecular properties commonly used to define these classes are discriminant in the hilus of the dentate gyrus. Here, using patch-clamp combined with single cell RT-PCR, we compare the relevance of commonly used electrophysiological and molecular features for the clustering of GABAergic interneurons sampled from the mouse hilus and primary sensory cortex. While unsupervised clustering groups cortical interneurons into well-established classes, it fails to provide a convincing partition of hilar interneurons. Statistical analysis based on resampling indicates that hilar and cortical GABAergic interneurons share limited homology. While our results do not invalidate the use of classical molecular marker in the hilus, they indicate that classes of hilar interneurons defined by the expression of molecular markers do not exhibit strongly discriminating electrophysiological properties.
... These IPs can amplify the number of concurrently actively dividing cells in the developing brain (Noctor et al., 2004) and, as discussed later, convey unique properties to their daughter neurons. As progenitors divide, postmitotic neurons of the ventral telencephalon follow a well defined developmental sequence starting with their migration from their birthplace to their designated brain regions (Villar-Cerviño et al., 2015), progressively differentiating toward their final identity. During later postnatal stages, these immature neurons initially connect widely followed by periods of synaptic refinement and controlled apoptosis in maturing circuits (Fig. 1C). ...
... From the MGE, interneurons migrate longer distances to both the cortex and the striatum, again relying on differential expression of guidance molecules and receptors. For example, it is known that migration to cortical regions is guided by chemoattraction of semaphorin ligands (Sema3A and SemaF), and neuropilin receptors (Nrp1, Nrp2; Marin and Rubenstein, 2001;Andrews et al., 2017) expressed in cortical fated cells, whereas migration to the striatal region is regulated by neuregulin 1 and ErbB4 receptor tyrosine kinase 4 signaling (Villar-Cerviño et al., 2015). Any change in the expression of these transcription factors in postmitotic cells will redirect cells fated to a specific brain region (Villar-Cerviño et al., 2015). ...
... For example, it is known that migration to cortical regions is guided by chemoattraction of semaphorin ligands (Sema3A and SemaF), and neuropilin receptors (Nrp1, Nrp2; Marin and Rubenstein, 2001;Andrews et al., 2017) expressed in cortical fated cells, whereas migration to the striatal region is regulated by neuregulin 1 and ErbB4 receptor tyrosine kinase 4 signaling (Villar-Cerviño et al., 2015). Any change in the expression of these transcription factors in postmitotic cells will redirect cells fated to a specific brain region (Villar-Cerviño et al., 2015). The rapid downregulation of Nkx2.1 acts as a postmitotic transcriptional switch (Fig. 3B) in cortical fated cells, as it transcriptionally inhibits cortical migration cues such as Nrp2 (Butt et al., 2008;Nóbrega-Pereira et al., 2008). ...
Understanding how neurons of the striatum are formed and integrate into complex synaptic circuits is essential to provide insight into striatal function in health and disease. In this review, we summarize our current understanding of the development of striatal neurons and associated circuits with a focus on their embryonic origin. Specifically, we address the role of distinct types of embryonic progenitors, found in the proliferative zones of the ganglionic eminences in the ventral telencephalon, in the generation of diverse striatal interneurons and projection neurons. Indeed, recent evidence would suggest that embryonic progenitor origin dictates key characteristics of postnatal cells, including their neurochemical content, their location within striatum, and their long-range synaptic inputs. We also integrate recent observations regarding embryonic progenitors in cortical and other regions and discuss how this might inform future research on the ganglionic eminences. Last, we examine how embryonic progenitor dysfunction can alter striatal formation, as exemplified in Huntington’s disease and autism spectrum disorder, and how increased understanding of embryonic progenitors can have significant implications for future research directions and the development of improved therapeutic options.
... LGE and CGE) (Yau et al., 2003;Fox & Kornblum, 2005). Rodent ERBB4 is mainly expressed in MGE-derived GABAergic interneurons migrating to the cerebral cortex, and this expression was reported to be important in this tangential migration (Li et al., 2012;Rakic et al. 2015;Villar-Cerviño et al., 2015). In contrast, we found in human that ERBB4 is strikingly enriched in ...
Increasing interest in studies of prenatal human brain development, particularly using new single-cell genomics and anatomical technologies to create cell atlases, creates a strong need for accurate and detailed anatomical reference atlases. In this study, we present two cellular-resolution digital anatomical atlases for prenatal human brain at post-conceptional weeks (PCW) 15 and 21. Both atlases were annotated on sequential Nissl-stained sections covering brain-wide structures on the basis of combined analysis of cytoarchitecture, acetylcholinesterase staining and an extensive marker gene expression dataset. This high information content dataset allowed reliable and accurate demarcation of developing cortical and subcortical structures and their subdivisions. Furthermore, using the anatomical atlases as a guide, spatial expression of 37 and 5 genes from the brains respectively at PCW 15 and 21 was annotated, illustrating reliable marker genes for many developing brain structures. Finally, the present study uncovered several novel developmental features, such as the lack of an outer subventricular zone in the hippocampal formation and entorhinal cortex, and the apparent extension of both cortical (excitatory) and subcortical (inhibitory) progenitors into the prenatal olfactory bulb. These comprehensive atlases provide useful tools for visualization, targeting, imaging and interpretation of brain structures of prenatal human brain, and for guiding and interpreting the next generation of cell census and connectome studies.
... Several chemoattractive cues also guide the migration of interneurons. Neurogulin1 (NRG1) and its receptor, ErbB4 expressed by interneurons, is the controlling signal of interneuron tangential migration (Flames et al. 2004;Villar-Cerviño et al. 2015). As chemoattractants, NRG1/ErbB4 controls the tangential migration of interneurons from the MGE toward the striatum (Marín 2013;Villar-Cerviño et al. 2015). ...
... Neurogulin1 (NRG1) and its receptor, ErbB4 expressed by interneurons, is the controlling signal of interneuron tangential migration (Flames et al. 2004;Villar-Cerviño et al. 2015). As chemoattractants, NRG1/ErbB4 controls the tangential migration of interneurons from the MGE toward the striatum (Marín 2013;Villar-Cerviño et al. 2015). Brain-derived neurotrophic factor (BDNF) and neurotrophin-4 (NT4), acting through TrkB signaling, also control the tangential migration of interneurons (Polleux et al. 2002). ...
In mature mammalian brains, the endocannabinoid system (ECS) plays an important role in the regulation of synaptic plasticity and the functioning of neural networks. Besides, the ECS also contributes to the neurodevelopment of the central nervous system. Due to the increase in the medical and recreational use of cannabis, it is inevitable and essential to elaborate the roles of the ECS on neurodevelopment. GABAergic interneurons represent a group of inhibitory neurons that are vital in controlling neural network activity. However, the role of the ECS in the neurodevelopment of GABAergic interneurons remains to be fully elucidated. In this review, we provide a brief introduction of the ECS and interneuron diversity. We focus on the process of interneuron development and the role of ECS in the modulation of interneuron development, from the expansion of the neural stem/progenitor cells to the migration, specification and maturation of interneurons. We further discuss the potential implications of the ECS and interneurons in the pathogenesis of neurological and psychiatric disorders, including epilepsy, schizophrenia, major depressive disorder and autism spectrum disorder.
... In the latter case, DCC proteins may be non-functional and hypomorphic. Monoallelic frameshift and missense mutations may also present with a mixed phenotype, i.e., mirror movements with isolated ACC [16,17] EphB1 plays a role in regulating the migration of striatal interneurons, controlled by the Nkx2-1 factor [18]. By binding to tumor necrosis factor receptor 2, tumor necrosis factor α (TNF-α) upregulates the expression of the EphB2 receptor in neurons during neuroregeneration, which suggests a possible role of EphB2 in this process [19]. ...
Brain hemispheres are connected by commissural structures, which consist of white matter fiber tracts that spread excitatory stimuli to various regions of the cortex. This allows an interaction between the two cerebral halves. The largest commissure is the corpus callosum (CC) which is located inferior to the longitudinal fissure, serving as its lower border. Sometimes this structure is not completely developed, which results in the condition known as agenesis of the corpus callosum (ACC). The aim of this paper was to review the latest discoveries related to the genetic and metabolic background of ACC, including the genotype/phenotype correlations as well as the clinical and imaging symptomatology. Due to various factors, including genetic defects and metabolic diseases, the development of CC may be impaired in many ways, which results in complete or partial ACC. This creates several clinical implications, depending on the specificity of the malformation and other defects in patients. Epilepsy, motor impairment and intellectual disability are the most prevalent. However, an asymptomatic course of the disease is even more common. ACC presents with characteristic images on ultrasound and magnetic resonance imaging (MRI).
... After corticogenesis, the neurogenic niche of the iSVZ and oSVZ remains proliferative in neonates along the wall of the lateral ventricle in the site of former lateral ganglionic eminence, generating new neurons that populate the pre-frontal cortex and, partially, the olfactory bulb (81, 99) for a few months after birth. Subsequently, however, this activity declines dramatically, and, within 2 years, there is almost no detectable neurogenesis or migration (100)(101)(102)(103). Perinatally, SVZ stem cells differentiate and migrate along three specific pathways toward the anterior forebrain: (i) to the frontal lobe where they become interneurons (arc pathway) (103); (ii) to the medial pre-frontal cortex along the medial migratory stream (MMS); (iii) to the olfactory bulb along the RMS (104). ...
Neural stem cells (NSCs) have garnered significant scientific and commercial interest in the last 15 years. Given their plasticity, defined as the ability to develop into different phenotypes inside and outside of the nervous system, with a capacity of almost unlimited self-renewal, of releasing trophic and immunomodulatory factors, and of exploiting temporal and spatial dynamics, NSCs have been proposed for (i) neurotoxicity testing; (ii) cellular therapies to treat CNS diseases; (iii) neural tissue engineering and repair; (iv) drug target validation and testing; (v) personalized medicine. Moreover, given the growing interest in developing cell-based therapies to target neurodegenerative diseases, recent progress in developing NSCs from human-induced pluripotent stem cells has produced an analog of endogenous NSCs. Herein, we will review the current understanding on emerging conceptual and technological topics in the neural stem cell field, such as deep characterization of the human compartment, single-cell spatial-temporal dynamics, reprogramming from somatic cells, and NSC manipulation and monitoring. Together, these aspects contribute to further disentangling NSC plasticity to better exploit the potential of those cells, which, in the future, might offer new strategies for brain therapies.
... Since MGE-derived neurons are generated at different embryonic stages (Mi et al., 2018;Sandberg et al., 2018) and CINs proliferate along a caudal-rostral axis (Semba et al., 1988), future research may reveal which proliferation domains generate cholinergic cell subtypes. Subsequent to proliferation, cells use different migratory pathways that require the expression of specific receptors to detect chemoattractive and chemorepulsive cues (Wichterle et al., 2003;Gelman et al., 2012;Villar-Cerviño et al., 2015;Touzot et al., 2016). Therefore, development of cholinergic neurons that requires the accurate modulation of distinct transcriptional programs needs to be further investigated. ...
Cholinergic neurons comprise a small population of cells in the striatum but have fundamental roles in fine tuning brain function, and in the etiology of neurological and psychiatric disorders such as Parkinson’s disease (PD) or schizophrenia. The process of developmental cell specification underlying neuronal identity and function is an area of great current interest. There has been significant progress in identifying the developmental origins, commonalities in molecular markers, and physiological properties of the cholinergic neurons. Currently, we are aware of a number of key factors that promote cholinergic fate during development. However, the extent of cholinergic cell diversity is still largely underestimated. New insights into the biological basis of their specification indicate that cholinergic neurons may be far more diverse than previously thought. This review article, highlights the physiological features and the synaptic properties that segregate cholinergic cell subtypes. It provides an accurate picture of cholinergic cell diversity underlying their organization and function in neuronal networks. This review article, also discusses current challenges in deciphering the logic of the cholinergic cell heterogeneity that plays a fundamental role in the control of neural processes in health and disease.
... Overexpression of Nkx2.1, a transcription factor expressed in the developing MGE, enhances the migration of interneurons to the striatum and reduces migration to the cortex [69], suggesting that Nkx2.1 is involved in the specification of striatal interneurons. Reports show that specific guidance cues consisting of diffusible molecules are involved in the radial migration of projection neurons [70] and tangential migration of interneurons [71][72][73] in the developing striatum. For example, netrin-1, which is secreted from the ventricular zone of the LGE, repels neuronal progenitors derived from the LGE and thereby promotes radial migration and differentiation of striatal projection neurons [70]. ...
... For example, netrin-1, which is secreted from the ventricular zone of the LGE, repels neuronal progenitors derived from the LGE and thereby promotes radial migration and differentiation of striatal projection neurons [70]. The tangential migration of striatal interneurons from the MGE was shown to be regulated by a combination of Nrg1/ErbB4 chemoattraction and EphB/ephrinB chemorepulsion [73]. Recent findings in mice showed that aberrant compartmentalization of the striatum induced by valproic acid administration during striosomal neurogenesis resulted in autism spectrum disorder-like phenotypes [74]. ...
The intricate neuronal architecture of the striatum plays a pivotal role in the functioning of the basal ganglia circuits involved in the control of various aspects of motor, cognitive, and emotional functions. Unlike the cerebral cortex, which has a laminar structure, the striatum is primarily composed of two functional subdivisions (i.e., the striosome and matrix compartments) arranged in a mosaic fashion. This review addresses whether striatal compartmentalization is present in non-mammalian vertebrates, in which simple cognitive and behavioral functions are executed by primitive sensori-motor systems. Studies show that neuronal subpopulations that share neurochemical and connective properties with striosomal and matrix neurons are present in the striata of not only anamniotes (fishes and amphibians), but also amniotes (reptiles and birds). However, these neurons do not form clearly segregated compartments in these vertebrates, suggesting that such compartmentalization is unique to mammals. In the ontogeny of the mammalian forebrain, the later-born matrix neurons disperse the early-born striosome neurons into clusters to form the compartments in tandem with the development of striatal afferents from the cortex. We propose that striatal compartmentalization in mammals emerged in parallel with the evolution of the cortex and possibly enhanced complex processing of sensory information and behavioral flexibility phylogenetically.
