Decreased density of cholinergic interneurons in striatal territories in Williams syndrome.

Williams syndrome (WS) is a rare neurodevelopmental disorder caused by the hemideletion of approximately 25-28 genes at 7q11.23. Its unusual social and cognitive phenotype is most strikingly characterized by the disinhibition of social behavior, in addition to reduced global IQ, with a relative sparing of language ability.

Neurodevelopmental disorders of the prefrontal cortex in an evolutionary context.

The prefrontal cortex consists of several cytoarchitectonically defined areas that are involved in higher-order cognitive and emotional processing. The areas are highly variable in terms of organization of cortical layers and distribution of specific neuronal classes, and are affected in neurodevelopmental and psychiatric disorders. Here the focus is on microstructural anatomical characteristics of human prefrontal cortex in an evolutionary context with special emphasis on Williams syndrome.

Serotonergic innervation of the human amygdala and evolutionary implications.

Objectives: The serotonergic system is involved in the regulation of socio-emotional behavior and heavily innervates the amygdala, a key structure of social brain circuitry. We quantified serotonergic axon density of the four major nuclei of the amygdala in humans, and examined our results in light of previously published data sets in chimpanzees and bonobos.

Materials And Methods: Formalin-fixed postmortem tissue sections of the amygdala from six humans were stained for serotonin transporter (SERT) utilizing immunohistochemistry.

Species-specific maturation profiles of human, chimpanzee and bonobo neural cells.

Comparative analyses of neuronal phenotypes in closely related species can shed light on neuronal changes occurring during evolution. The study of post-mortem brains of nonhuman primates (NHPs) has been limited and often does not recapitulate important species-specific developmental hallmarks. We utilize induced pluripotent stem cell (iPSC) technology to investigate the development of cortical pyramidal neurons following migration and maturation of cells grafted in the developing mouse cortex.

Biphasic dendritic growth of dorsolateral prefrontal cortex associative neurons and early cognitive development.

Aim: To analyze postnatal development and life-span changes of apical dendrite side branches (oblique dendrites) from associative layer IIIC magnopyramidal neurons in the human dorsolateral prefrontal cortex and to compare the findings with the previously established pattern of basal dendrite development.

Methods: We analyzed dendritic morphology from 352 rapid-Golgi impregnated neurons (10-18 neurons per subject) in Brodmann area 9 from the post-mortem tissue of 25 subjects ranging in age from 1 week to 91 years. Data were collected in the period between 1994 and 1996, and the analysis was performed between September 2017 and February 2018.

Increased glia density in the caudate nucleus in williams syndrome: Implications for frontostriatal dysfunction in autism.

Williams syndrome (WS) is a rare neurodevelopmental disorder with a well-described, known genetic etiology. In contrast to Autism Spectrum Disorders (ASD), WS has a unique phenotype characterized by global reductions in IQ and visuospatial ability, with relatively preserved language function, enhanced reactivity to social stimuli and music, and an unusual eagerness to interact socially with strangers. A duplication of the deleted region in WS has been implicated in a subset of ASD cases, defining a spectrum of genetic and behavioral variation at this locus defined by these opposite extremes in social behavior.

Basal Dendritic Morphology of Cortical Pyramidal Neurons in Williams Syndrome: Prefrontal Cortex and Beyond.

Williams syndrome (WS) is a unique neurodevelopmental disorder with a specific behavioral and cognitive profile, which includes hyperaffiliative behavior, poor social judgment, and lack of social inhibition. Here we examined the morphology of basal dendrites on pyramidal neurons in the cortex of two rare adult subjects with WS. Specifically, we examined two areas in the prefrontal cortex (PFC)-the frontal pole (Brodmann area 10) and the orbitofrontal cortex (Brodmann area 11)-and three areas in the motor, sensory, and visual cortex (BA 4, BA 3-1-2, BA 18).

A dual comparative approach: integrating lines of evidence from human evolutionary neuroanatomy and neurodevelopmental disorders.

The evolution of the human brain has been marked by a nearly 3-fold increase in size since our divergence from the last common ancestor shared with chimpanzees and bonobos. Despite increased interest in comparative neuroanatomy and phylogenetic methods, relatively little is known regarding the effects that this enlargement has had on its internal organization, and how certain areas of the brain have differentially expanded over evolutionary time. Analyses of the microstructure of several regions of the human cortex and subcortical structures have demonstrated subtle changes at the cellular and molecular level, suggesting that the human brain is more than simply a 'scaled-up' primate brain.

Micro RNA detection in long-term fixed tissue of cortical glutamatergic pyramidal neurons after targeted laser-capture neuroanatomical microdissection.

Background: Formalin fixation (FF) is the standard and most common method for preserving postmortem brain tissue. FF stabilizes cellular morphology and tissue architecture, and can be used to study the distinct morphologic and genetic signatures of different cell types. Although the procedure involved in FF degrades messenger RNA over time, an alternative approach is to use small RNAs (sRNAs) for genetic analysis associated with cell morphology.

Evolution, development, and plasticity of the human brain: from molecules to bones.

Neuroanatomical, molecular, and paleontological evidence is examined in light of human brain evolution. The brain of extant humans differs from the brains of other primates in its overall size and organization, and differences in size and organization of specific cortical areas and subcortical structures implicated into complex cognition and social and emotional processing. The human brain is also characterized by functional lateralizations, reflecting specializations of the cerebral hemispheres in humans for different types of processing, facilitating fast and reliable communication between neural cells in an enlarged brain.

Novel tools, classic techniques: evolutionary studies using primate pluripotent stem cells.

Recent applications of genomic tools on the analysis of alterations unique to our species coupled with a growing number of neuroanatomical studies across primates provide an unprecedented opportunity to compile different levels of human brain evolution into a complex whole. Applications of induced pluripotent stem cell (iPSC) technology, capable of reprogramming somatic tissue of different species and generating species-specific neuronal phenotypes, for the first time offer an opportunity to test specific evolutionary hypotheses in a field of inquiry that has been long plagued by the limited availability of research specimens. In this review, we will focus specifically on the experimental role of iPSC technology as applied to the analysis of neocortical pyramidal neurons.