Neuronal and non-neuronal scaling across brain regions within an intercross of domestic and wild chickens
The allometric scaling of the brain size and neuron number across species has been extensively studied in recent years. With the exception of primates, parrots, and songbirds, larger brains have more neurons but relatively lower neuronal densities than smaller brains. Conversely, when considering within-population variability, it has been shown that mice with larger brains do not necessarily have more neurons but rather more neurons in the brain reflect higher neuronal density. To what extent this intraspecific allometric scaling pattern of the brain applies to individuals from other species remains to be explored. Here, w...
Source: Frontiers in Neuroanatomy - November 25, 2022 Category: Neurology Source Type: research
The amygdala –insula–medial prefrontal cortex–lateral prefrontal cortex pathway and its disorders
Smith and Lane have suggested a model of emotion processing with at least three stations: areas like the amygdala, which process discrete body features areas like the anterior insula, which process whole-body patterns and areas like the medial prefrontal cortex, which process emotion concepts. Ben Shalom and Bonneh have suggested a model of the prefrontal cortex, in which medial BA 9 integrates emotional states, and lateral BA 9 performs selection/inhibition on these states. Taken together, the current paper suggests a pathway for emotion processing with at least four stations: areas like the amygdala, which process discre...
Source: Frontiers in Neuroanatomy - November 24, 2022 Category: Neurology Source Type: research
Morphological investigations of endomorphin-2 and spinoparabrachial projection neurons in the spinal dorsal horn of the rat
It has been proved that endomorphin-2 (EM2) produced obvious analgesic effects in the spinal dorsal horn (SDH), which existed in our human bodies with remarkable affinity and selectivity for the μ-opioid receptor (MOR). Our previous study has demonstrated that EM2 made synapses with the spinoparabrachial projection neurons (PNs) in the SDH and inhibited their activities by reducing presynaptic glutamate release. However, the morphological features of EM2 and the spinoparabrachial PNs in the SDH have not been completely investigated. Here, we examined the morphological features of EM2 and the spinoparabrachial PNs by using...
Source: Frontiers in Neuroanatomy - November 23, 2022 Category: Neurology Source Type: research
The heterogeneity of astrocytes in glaucoma
Glaucoma is a leading cause of blindness with progressive degeneration of retinal ganglion cells. Aging and increased intraocular pressure (IOP) are major risk factors. Lowering IOP does not always stop the disease progression. Alternative ways of protecting the optic nerve are intensively studied in glaucoma. Astrocytes are macroglia residing in the retina, optic nerve head (ONH), and visual brain, which keep neuronal homeostasis, regulate neuronal activities and are part of the immune responses to the retina and brain insults. In this brief review, we discuss the activation and heterogeneity of astrocytes in the retina, ...
Source: Frontiers in Neuroanatomy - November 17, 2022 Category: Neurology Source Type: research
Hippocampal adaptation to high altitude: a neuroanatomic profile of hippocampal subfields in Tibetans and acclimatized Han Chinese residents
The hippocampus is highly plastic and vulnerable to hypoxia. However, it is unknown whether and how it adapts to chronic hypobaric hypoxia in humans. With a unique sample of Tibetans and acclimatized Han Chinese individuals residing on the Tibetan plateau, we aimed to build a neuroanatomic profile of the altitude-adapted hippocampus by measuring the volumetric differences in the whole hippocampus and its subfields. High-resolution T1-weighted magnetic resonance imaging was performed in healthy Tibetans (TH, n = 72) and healthy Han Chinese individuals living at an altitude of more than 3,500 m (HH, n = 27). In addition, hea...
Source: Frontiers in Neuroanatomy - November 17, 2022 Category: Neurology Source Type: research
A morphometric analysis of the circumolivary fiber bundle of the human brainstem
The circumolivary fiber bundle (CFB) is considered to be an anatomical variation, which can be found on the surface of the human medulla oblongata. The macroscopical fiber bundle runs downwards from either the anterior median fissure, the pyramid, or both, around the inferior pole of the olive and turns upwards to reach the restiform body of the inferior cerebellar peduncle. Multiple fiber systems feed the constitution of the CFB (collateral corticospinal fibers, fibers connecting to the reticular formation, anterior external arcuate fibers). With this examination we provide a systematic analysis of the frequency of occurr...
Source: Frontiers in Neuroanatomy - November 16, 2022 Category: Neurology Source Type: research
Frontal aslant tract in the non-dominant hemisphere: A systematic review of anatomy, functions, and surgical applications
We report here the anatomy and functions of the frontal aslant tract (FAT) in the non-dominant hemisphere (usually the right hemisphere). Despite the structural symmetry between the right and left FAT, these two tracts seem to display functional asymmetry, with several brain functions in common, but others, such as visuospatial and social cognition, music processing, shifting attention or working memory, more exclusively associated with the right FAT. Further studies are required to determine whether damage to the right FAT causes permanent cognitive impairment. Such studies will constitute the best means of testing whethe...
Source: Frontiers in Neuroanatomy - November 14, 2022 Category: Neurology Source Type: research
HOA2.0-ComPaRe: A next generation Harvard-Oxford Atlas comparative parcellation reasoning method for human and macaque individual brain parcellation and atlases of the cerebral cortex
Comparative structural neuroanatomy is a cornerstone for understanding human brain structure and function. A parcellation framework that relates systematically to fundamental principles of histological organization is an essential step in generating structural comparisons between species. In the present investigation, we developed a comparative parcellation reasoning system (ComPaRe), which is a formal ontological system in human and non-human primate brains based on the cortical cytoarchitectonic mapping used for both species as detailed by Brodmann. ComPaRe provides a theoretical foundation for mapping neural systems in ...
Source: Frontiers in Neuroanatomy - November 10, 2022 Category: Neurology Source Type: research
The large numbers of minicolumns in the primary visual cortex of humans, chimpanzees and gorillas are related to high visual acuity
Minicolumns are thought to be a fundamental neural unit in the neocortex and their replication may have formed the basis of the rapid cortical expansion that occurred during primate evolution. We sought evidence of minicolumns in the primary visual cortex (V-1) of three great apes, three rodents and representatives from three other mammalian orders: Eulipotyphla (European hedgehog), Artiodactyla (domestic pig) and Carnivora (ferret). Minicolumns, identified by the presence of a long bundle of radial, myelinated fibers stretching from layer III to the white matter of silver-stained sections, were found in the human, chimpan...
Source: Frontiers in Neuroanatomy - November 9, 2022 Category: Neurology Source Type: research
Development of subdomains in the medial pallium of Xenopus laevis and Trachemys scripta: Insights into the anamniote-amniote transition
In all vertebrates, the most dorsal region of the telencephalon gives rise to the pallium, which in turn, is formed by at least four evolutionarily conserved histogenetic domains. Particularly in mammals, the medial pallium generates the hippocampal formation. Although this region is structurally different among amniotes, its functions, attributed to spatial memory and social behavior, as well as the specification of the histogenetic domain, appears to be conserved. Thus, the aim of the present study was to analyze this region by comparative analysis of the expression patterns of conserved markers in two vertebrate models:...
Source: Frontiers in Neuroanatomy - November 3, 2022 Category: Neurology Source Type: research
Morphology of the murine choroid plexus: Attachment regions and spatial relation to the subarachnoid space
The choroid plexus has recently been identified as a possible migration route for peripheral immune cells into the central nervous system. For future investigation of this route, profound knowledge of the morphology of the murine choroid plexus is a prerequisite. We here present a detailed morphological description of the murine choroid plexus, its attachment regions as well as its spatial relation to the subarachnoid space. We used micro-computed tomography of immersion-contrasted fixated brains to generate three-dimensional models of the ventricle system and the choroid plexus and aligned micro-computed tomography-based ...
Source: Frontiers in Neuroanatomy - October 31, 2022 Category: Neurology Source Type: research
Chronic treatment with corticosterone increases the number of tyrosine hydroxylase-expressing cells within specific nuclei of the brainstem reticular formation
Cushing's syndrome is due to increased glucocorticoid levels in the body, and it is characterized by several clinical alterations which concern both vegetative and behavioral functions. The anatomical correlates of these effects remain largely unknown. Apart from peripheral effects induced by corticosteroids as counter-insular hormones, only a few reports are available concerning the neurobiology of glucocorticoid-induced vegetative and behavioral alterations. In the present study, C57 Black mice were administered daily a chronic treatment with corticosterone in drinking water. This treatment produces a significant and sel...
Source: Frontiers in Neuroanatomy - October 28, 2022 Category: Neurology Source Type: research
Repetitively burst-spiking neurons in reeler mice show conserved but also highly variable morphological features of layer Vb-fated “thick-tufted” pyramidal cells
Reelin is a large extracellular glycoprotein that is secreted by Cajal-Retzius cells during embryonic development to regulate neuronal migration and cell proliferation but it also seems to regulate ion channel distribution and synaptic vesicle release properties of excitatory neurons well into adulthood. Mouse mutants with a compromised reelin signaling cascade show a highly disorganized neocortex but the basic connectional features of the displaced excitatory principal cells seem to be relatively intact. Very little is known, however, about the intrinsic electrophysiological and morphological properties of individual cell...
Source: Frontiers in Neuroanatomy - October 28, 2022 Category: Neurology Source Type: research
Cannabinoid CB1 receptor expression in oligodendrocyte progenitors of the hippocampus revealed by the NG2-EYFP-knockin mouse
Adult oligodendrocyte progenitor cells (OPCs) give rise to myelinating oligodendrocytes through life and play crucial roles in brain homeostasis and plasticity during health and disease. Cannabinoid compounds acting through CB1 receptors promote the proliferation and differentiation of OPCs in vitro and facilitate developmental myelination and myelin repair in vivo. However, CB1 receptor expression in adult OPCs in situ has not been corroborated by anatomical studies and the contribution of this receptor population to the (re)myelination effects of cannabinoids remains a matter of debate. Using electron microscopy methods ...
Source: Frontiers in Neuroanatomy - October 28, 2022 Category: Neurology Source Type: research
Editorial: The human brain multiscale imaging challenge
(Source: Frontiers in Neuroanatomy)
Source: Frontiers in Neuroanatomy - October 27, 2022 Category: Neurology Source Type: research
