VENs might correspond to ∼3% of all neurons in layer V in the ACC ( Fajardo et al., 2008 see comments about their relative abundance in Banovac et al., 2021), being more numerous in the ACC and FI of humans than in apes ( Allman et al., 2010). In humans, VENs have been reported mainly in the anterior cingulate cortex (ACC) and frontoinsular cortex (FI Raghanti et al., 2015 Banovac et al., 2019, 2021 Correa-Júnior et al., 2020 and references therein), but also in the dorsolateral prefrontal cortex (Brodmann area 9 Fajardo et al., 2008) and in the medial frontopolar prefrontal cortex (Brodmann area 10 González-Acosta et al., 2018). Von Economo neurons (VENs) have a peculiar phylogenetic and ontogenetic development and are characterized by an elongated spindle-shaped or rod-shaped cell body mainly found in the cortical layer V of restricted brain areas of some species, including humans and other primates, but not in all mammals ( Nimchinsky et al., 1995 Allman et al., 2005, 2010 Hakeem et al., 2009 Cauda et al., 2014 Raghanti et al., 2015 Hodge et al., 2020 Jacob et al., 2021).
#Spindle shaped Pc
These findings would include these spindle-shaped cells in the synaptic and information processing by the default mode network and for general intelligence in healthy individuals and in neuropsychiatric disorders involving the PC in the context of the PMC functioning. The presence of spindle-shaped neurons and the current discussion on the morphology of putative VENs address the need for an in-depth neurochemical and transcriptomic characterization of the PC cytoarchitecture. We discuss the morphology of these cells and those considered VENs in cortical areas forming integrated brain networks for higher-order activities. Other spindle-shaped cells were observed with straight dendritic shafts and rare branches or with an axon emerging from the soma. The primary dendritic shafts give rise to thin collateral branches with a radial orientation, and pleomorphic spines were observed with a sparse to moderate density along the dendritic length. From three-dimensional (3D) reconstructed images, we describe the cell body, two main longitudinally oriented ascending and descending dendrites as well as the occurrence of spines from proximal to distal segments. The adapted “single-section” Golgi method for postmortem tissue was used to study these neurons close to pyramidal ones in layer V until merging with layer VI polymorphic cells. Here, we describe the presence of Nissl-stained elongated spindle-shaped neurons (suggestive of von Economo neurons, VENs) in the cortical layer V of the anterior and central PC of adult humans. The human posteromedial cortex (PMC), which includes the precuneus (PC), represents a multimodal brain area implicated in emotion, conscious awareness, spatial cognition, and social behavior. 5Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany.4Department of Medical Clinics/Neurology, Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, Brazil.3Graduate Program in Biosciences, Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, Brazil.
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