scholarly journals A neural progenitor mitotic wave is required for asynchronous axon outgrowth and morphology

2021 ◽  
Author(s):  
Jérôme Lacoste ◽  
Hédi Soula ◽  
Angélique Burg ◽  
Agnès Audibert ◽  
Pénélope Darnat ◽  
...  
Keyword(s):  
Sensory Neurons ◽  
Temporal Order ◽  
Secreted Protein ◽  
Branching Pattern ◽  
Neural Connectivity ◽  
Grooming Behavior ◽  
Mitotic Wave ◽  
Neural Processes ◽  
Neural Connection ◽  
Inhibitory Interactions

SUMMARYSpatiotemporal mechanisms generating neural diversity are fundamental for understanding neural processes. Here, we investigated how neural connection diversity arises from neurons coming from identical progenitors. In the dorsal thorax of Drosophila, rows of mechanosensory organs originate from the division of sensory organ progenitor (SOPs). We show that in each row of the notum, a central SOP divides first, then neighboring SOPs divide, and so on. This centrifugal wave of mitoses depends on cell-cell inhibitory interactions mediated by SOP cytoplasmic protrusions and Scabrous, a secreted protein interacting with the Delta/Notch complex. When scabrous was downregulated, the mitotic wave was abolished, axonal growth was more synchronous, axonal terminals had a complex branching pattern and fly behavior was impaired. We propose that the temporal order of progenitor divisions influences the birth order of sensory neurons which is critical for correct axon wiring and appropriate grooming behavior, supporting the idea that developmental timing controls neural connectivity.

Spatiotemporal factors influence sound-source segregation in localization behavior

2020 ◽  
Author(s):  
Guus Christian van Bentum ◽  
Marc Mathijs van Wanrooij ◽  
A. John Van Opstal
Keyword(s):  
Temporal Order ◽  
Weighted Average ◽  
Spatial Separation ◽  
Stimulus Location ◽  
Spatial Proximity ◽  
Sound Source Segregation ◽  
Close Spatial Proximity ◽  
Inhibitory Interactions ◽  
Localization Behavior ◽  
Sensorimotor Map

To program a goal-directed response in the presence of acoustic reflections, the audio-motor system should suppress the detection of time-delayed sources. We examined the effects of spatial separation and inter-stimulus delay on the ability of human listeners to localize a pair of broadband sounds in the horizontal plane. Participants indicated how many sounds were heard and where these were perceived by making one or two head-orienting localization responses. Results suggest that perceptual fusion of the two sounds depends on delay and spatial separation. Leading and lagging stimuli in close spatial proximity required longer stimulus delays to be perceptually separated than those further apart. Whenever participants heard one sound, their localization responses for synchronous sounds were oriented to a weighted average of both source locations. For short delays, responses were directed towards the leading stimulus location. Increasing spatial separation enhanced this effect. For longer delays, responses were again directed towards a weighted average. When participants perceived two sounds, the first and the second response were directed to either of the leading and lagging source locations. Perceived locations were interchanged often in their temporal order (in ~40% of trials). We show that the percept of two sounds occurring requires sufficient spatiotemporal separation, after which localization can be performed with high accuracy. We propose that the percept of temporal order of two concurrent sounds results from a different process than localization, and discuss how dynamic lateral excitatory-inhibitory interactions within a spatial sensorimotor map could explain the findings.

Odorant Receptors in the Formation of the Olfactory Bulb Circuitry

Physiology ◽  
2012 ◽  
Vol 27 (4) ◽  
pp. 200-212 ◽  
Author(s):  
Claudia Lodovichi ◽  
Leonardo Belluscio
Keyword(s):  
Olfactory Bulb ◽  
Axon Guidance ◽  
Sensory Neurons ◽  
Odorant Receptors ◽  
Olfactory Sensory Neurons ◽  
Neural Connectivity ◽  
Axon Terminals ◽  
Primary Function

In mammals, smell is mediated by odorant receptors expressed by sensory neurons in the nose. These specialized receptors are found both on olfactory sensory neurons' cilia and axon terminals. Although the primary function of ciliary odorant receptors is to detect odorants, their axonal role remains unclear but is thought to involve axon guidance. This review discusses findings that show axonal odorant receptors are indeed functional and capable of modulating neural connectivity.

scholarly journals Axon terminals control endolysosome diffusion to support synaptic remodelling

2021 ◽  
Vol 4 (8) ◽  
pp. e202101105
Author(s):  
Beatrice Terni ◽  
Artur Llobet
Keyword(s):  
Diffusion Coefficient ◽  
Sensory Neurons ◽  
Secreted Protein ◽  
Protein Homeostasis ◽  
Degradation Mechanisms ◽  
Axon Terminals ◽  
Glomerular Layer ◽  
Vesicle Pools ◽  
Acidic Organelles ◽  
Synaptic Remodelling

Endolysosomes are acidic organelles formed by the fusion of endosomes with lysosomes. In the presynaptic compartment they contribute to protein homeostasis, the maintenance of vesicle pools and synaptic stability. Here, we evaluated the mobility of endolysosomes found in axon terminals of olfactory sensory neurons of Xenopus tropicalis tadpoles. F-actin restricts the motion of these presynaptic acidic organelles which is characterized by a diffusion coefficient of 6.7 × 10−3 μm2·s−1. Local injection of secreted protein acidic and rich in cysteine (SPARC) in the glomerular layer of the olfactory bulb disrupts the structure of synaptic F-actin patches and increases the presence and mobility of endolysosomal organelles found in axon terminals. The increased motion of endolysosomes is localized to the presynaptic compartment and does not promote their access to axonal regions for retrograde transportation to the cell body. Local activation of synaptic degradation mechanisms mediated by SPARC coincides with a loss of the ability of tadpoles to detect waterborne odorants. Together, these observations show that the diffusion of presynaptic endolysosomes increases during conditions of synaptic remodelling to support their local degradative activity.

Temporal Order of Neural Progenitor Division Controls Neural Connectivity

2021 ◽  
Author(s):  
Jérôme Lacoste ◽  
Hedi Soula ◽  
Angélique Burg ◽  
Agnès Audibert ◽  
Pénélope Darnat ◽  
...  
Keyword(s):  
Temporal Order ◽  
Neural Progenitor ◽  
Neural Connectivity

Glucuronyl 3-sulfate occurs exclusively on distal unmyelinated terminals of selected sensory neurons in the peripheral nervous system

1995 ◽  
Vol 53 ◽  
pp. 958-959
Author(s):  
S.S. Spicer ◽  
B.A. Schulte
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Cerebral Cortex ◽  
Peripheral Nervous System ◽  
Sensory Neurons ◽  
Sensory Nerves ◽  
Tissue Antigens ◽  
The Central Nervous System ◽  
The Brain ◽  
Leu 7

Generation of monoclonal antibodies (MAbs) against tissue antigens has yielded several (VC1.1, HNK- 1, L2, 4F4 and anti-leu 7) which recognize the unique sugar epitope, glucuronyl 3-sulfate (Glc A3- SO4). In the central nervous system, these MAbs have demonstrated Glc A3-SO4 at the surface of neurons in the cerebral cortex, the cerebellum, the retina and other widespread regions of the brain.Here we describe the distribution of Glc A3-SO4 in the peripheral nervous system as determined by immunostaining with a MAb (VC 1.1) developed against antigen in the cat visual cortex. Outside the central nervous system, immunoreactivity was observed only in peripheral terminals of selected sensory nerves conducting transduction signals for touch, hearing, balance and taste. On the glassy membrane of the sinus hair in murine nasal skin, just deep to the ringwurt, VC 1.1 delineated an intensely stained, plaque-like area (Fig. 1). This previously unrecognized structure of the nasal vibrissae presumably serves as a tactile end organ and to our knowledge is not demonstrable by means other than its selective immunopositivity with VC1.1 and its appearance as a densely fibrillar area in H&E stained sections.

Ultrastructural study on the development of rat amygdaloid body

1990 ◽  
Vol 48 (3) ◽  
pp. 432-433
Author(s):  
A. Manolova ◽  
S. Manolov
Keyword(s):  
Nerve Cells ◽  
Amygdaloid Complex ◽  
Amygdaloid Body ◽  
Thin Ring ◽  
Morphological Criteria ◽  
Neural Processes ◽  
Abundant Cytoplasm ◽  
Level 1 ◽  
Few Data ◽  
Oval Shape

Relatively few data on the development of the amygdaloid complex are available only at the light microscopic level (1-3). The existence of just general morphological criteria requires the performance of other investigations in particular ultrastructural in order to obtain new and more detailed information about the changes in the amygdaloid complex during development.The prenatal and postnatal development of rat amygdaloid complex beginning from the 12th embrionic day (ED) till the 33rd postnatal day (PD) has been studied. During the early stages of neurogenesis (12ED), the nerve cells were observed to be closely packed, small-sized, with oval shape. A thin ring of cytoplasm surrounded their large nuclei, their nucleoli being very active with various size and form (Fig.1). Some cells possessed more abundant cytoplasm. The perikarya were extremely rich in free ribosomes. Single sacs of the rough endoplasmic reticulum and mitochondria were observed among them. The mitochondria were with light matrix and possessed few cristae. Neural processes were viewed to sprout from some nerve cells (Fig.2). Later the nuclei were still comparatively large and with various shape.

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