In Search for the Avian Trigeminal Magnetic Sensor: Distribution of Peripheral and Central Terminals of Ophthalmic Sensory Neurons in the Night-Migratory Eurasian Blackcap (Sylvia atricapilla)
In night-migratory songbirds, neurobiological and behavioral evidence suggest the existence of a magnetic sense associated with the ophthalmic branch of the trigeminal nerve (V1), possibly providing magnetic positional information. Curiously, neither the unequivocal existence, structural nature, nor the exact location of any sensory structure has been revealed to date. Here, we used neuronal tract tracing to map both the innervation fields in the upper beak and the detailed trigeminal brainstem terminations of the medial and lateral V1 subbranches in the night-migratory Eurasian Blackcap (Sylvia atricapilla). The medial V1...
Source: Frontiers in Neuroanatomy - March 7, 2022 Category: Neurology Source Type: research
The Olfactory Tract: Basis for Future Evolution in Response to Rapidly Changing Ecological Niches
Within the forebrain the olfactory sensory system is unique from other sensory systems both in the projections of the olfactory tract and the ongoing neurogenic potential, characteristics conserved across vertebrates. Olfaction plays a crucial role in behaviors such as mate choice, food selection, homing, escape from predators, among others. The olfactory forebrain is intimately associated with the limbic system, the region of the brain involved in learning, memory, and emotions through interactions with the endocrine system and the autonomic nervous system. Previously thought to lack a limbic system, we now know that tele...
Source: Frontiers in Neuroanatomy - March 3, 2022 Category: Neurology Source Type: research
The Number and Distinct Clustering Patterns of Voltage-Gated Calcium Channels in Nerve Terminals
In this study, we summarize how the morphological parameters of CaV2 distribution obtained using SDS-FRL differ depending on the different types of synapses and could correspond to functional properties in synaptic transmission. (Source: Frontiers in Neuroanatomy)
Source: Frontiers in Neuroanatomy - February 24, 2022 Category: Neurology Source Type: research
Programmed Cell Death and Autophagy in an in vitro Model of Spontaneous Neuroretinal Degeneration
This study reinforces the idea that cell death mechanisms are closely interconnected and provides new information about molecular signaling and autophagy along the retinal degeneration process. (Source: Frontiers in Neuroanatomy)
Source: Frontiers in Neuroanatomy - February 11, 2022 Category: Neurology Source Type: research
Gli2-Mediated Shh Signaling Is Required for Thalamocortical Projection Guidance
In conclusion, the alteration of Gli2-mediated Shh signaling produces an erroneous specification of several territories related with the thalamocortical axons. This is translated into a huge modification in the pathfinding signaling mechanisms needed for the correct wiring of the thalamocortical axons. (Source: Frontiers in Neuroanatomy)
Source: Frontiers in Neuroanatomy - February 10, 2022 Category: Neurology Source Type: research
The Evolution of Visual Roles – Ancient Vision Versus Object Vision
Just like other complex biological features, image vision (multi-pixel light sensing) did not evolve suddenly. Animal visual systems have a long prehistory of non-imaging light sensitivity. The first spatial vision was likely very crude with only few pixels, and evolved to improve orientation behaviors previously supported by single-channel directional photoreception. The origin of image vision was simply a switch from single to multiple spatial channels, which improved the behaviors for finding a suitable habitat and position itself within it. Orientation based on spatial vision obviously involves active guidance of behav...
Source: Frontiers in Neuroanatomy - February 9, 2022 Category: Neurology Source Type: research
Beta3Gn-T7 Is a Keratan Sulfate β1,3 N-Acetylglucosaminyltransferase in the Adult Brain
In this study, we show by a method of gene targeting that Beta3Gn-T7, encoded by B3gnt7, is a major Beta3Gn-T for the synthesis of KS in neuropils and the perineuronal region in the adult brain. Intriguingly, the B3gnt7 gene is selectively expressed in oligodendrocyte precursor cells (OPCs) and oligodendrocytes similar to that of GlcNAc6ST3. These results indicate that Beta3Gn-T7 in oligodendrocyte lineage cells may play a role in the formation of neuropils and perineuronal nets in the adult brain through the synthesis of R-10G-positive KS-modified proteoglycan. (Source: Frontiers in Neuroanatomy)
Source: Frontiers in Neuroanatomy - February 9, 2022 Category: Neurology Source Type: research
Neuromeric Distribution of Nicotinamide Adenine Dinucleotide Phosphate-Diaphorase Activity in the Adult Lamprey Brain
This study reports for the first time the distribution and morphological characterization of nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d; a reliable marker of nitric oxide synthase activity) positive elements in the central nervous system of the adult river lamprey (Lampetra fluviatilis) on the framework of the neuromeric model and compares their cytoarchitectonic organization with that of gnathostomes. Both NADPH-d exhibiting cells and fibers were observed in all major divisions of the lamprey brain as well as in the spinal cord. In the secondary prosencephalon, NADPH-d positive cells were observed in ...
Source: Frontiers in Neuroanatomy - February 7, 2022 Category: Neurology Source Type: research
Immunohistochemical Characterisation of the Whale Retina
In conclusion, the whale retina differs from that of terrestrial mammals. Their monochromatic rod vision due to the evolutionary loss of cone photoreceptors and the well-developed melanopsin-positive RGC network could, in part, explain the visual perception of these mammals in the deep sea. (Source: Frontiers in Neuroanatomy)
Source: Frontiers in Neuroanatomy - February 4, 2022 Category: Neurology Source Type: research
Conservation of the Direct and Indirect Pathway Dichotomy in Mouse Caudal Striatum With Uneven Distribution of Dopamine Receptor D1- and D2-Expressing Neurons
The striatum is one of the key nuclei for adequate control of voluntary behaviors and reinforcement learning. Two striatal projection neuron types, expressing either dopamine receptor D1 (D1R) or dopamine receptor D2 (D2R) constitute two independent output routes: the direct or indirect pathways, respectively. These pathways co-work in balance to achieve coordinated behavior. Two projection neuron types are equivalently intermingled in most striatal space. However, recent studies revealed two atypical zones in the caudal striatum: the zone in which D1R-neurons are the minor population (D1R-poor zone) and that in which D2R-...
Source: Frontiers in Neuroanatomy - February 4, 2022 Category: Neurology Source Type: research
An Efficient Method for the Isolation and Cultivation of Hypothalamic Neural Stem/Progenitor Cells From Mouse Embryos
In conclusion, we present a convenient and practical method for the isolation and cultivation of hypothalamic NSPCs that can be used in extensive hypothalamic studies. (Source: Frontiers in Neuroanatomy)
Source: Frontiers in Neuroanatomy - February 4, 2022 Category: Neurology Source Type: research
Differential Serotonergic Modulation of Principal Neurons and Interneurons in the Anterior Piriform Cortex
Originating from the brainstem raphe nuclei, serotonin is an important neuromodulator involved in a variety of physiological and pathological functions. Specific optogenetic stimulation of serotonergic neurons results in the divisive suppression of spontaneous, but not sensory evoked activity in the majority of neurons in the primary olfactory cortex and an increase in firing in a minority of neurons. To reveal the mechanisms involved in this dual serotonergic control of cortical activity we used a combination of in vitro electrophysiological recordings from identified neurons in the primary olfactory cortex, optogenetics ...
Source: Frontiers in Neuroanatomy - February 3, 2022 Category: Neurology Source Type: research
The Vestibular Column in the Mouse: A Rhombomeric Perspective
The vestibular column is located in the hindbrain between the sensory auditory (dorsal) and trigeminal (ventral) columns, spanning rhombomeres r1 (or r2) to r9. It contains the vestibular nuclear complex that receives sensory innervation from the labyrinthine end organs in the inner ear. Gene expression studies and experimental manipulations of developmental genes, particularly Hox genes and other developmental patterning genes, are providing insight into the morphological and functional organization of the vestibular nuclear complex, particularly from a segmental standpoint. Here, we will review studies of the classical v...
Source: Frontiers in Neuroanatomy - January 31, 2022 Category: Neurology Source Type: research
Prefrontal-Hippocampal Pathways Through the Nucleus Reuniens Are Functionally Biased by Brain State
Circuit-level communication between disparate brain regions is fundamental for the complexities of the central nervous system operation. Co-ordinated bouts of rhythmic activity between the prefrontal cortex (PFC) and hippocampus (HPC), in particular, are important for mnemonic processes. This is true during awake behavior, as well as during offline states like sleep. We have recently shown that the anatomically interposed thalamic nucleus reuniens (RE) has a role in coordinating slow-wave activity between the PFC and HPC. Here, we took advantage of spontaneous brain state changes occurring during urethane anesthesia in ord...
Source: Frontiers in Neuroanatomy - January 31, 2022 Category: Neurology Source Type: research
Deletion of β-Neurexins in Mice Alters the Distribution of Dense-Core Vesicles in Presynapses of Hippocampal and Cerebellar Neurons
In conclusion, based on the validation from the two deletion strategies in conditional and constitutive KO mice, two neuronal populations from the hippocampus and cerebellum, and two experimental protocols in cultured neurons and in the brain tissue, this study presented morphological evidence that the number of DCVs at synapses is altered in the absence of β-Nrxns. Our results therefore point to an unexpected contribution of β-Nrxns to the organization of neuropeptide and neuromodulator function, in addition to their more established role in synaptic vesicle release. (Source: Frontiers in Neuroanatomy)
Source: Frontiers in Neuroanatomy - January 31, 2022 Category: Neurology Source Type: research
