scholarly journals Embryonic and postnatal neurogenesis produce functionally distinct subclasses of dopaminergic neuron

2017 ◽  
Author(s):  
Elisa Galliano ◽  
Eleonora Franzoni ◽  
Marine Breton ◽  
Annisa N. Chand ◽  
Darren J. Byrne ◽  
...  
Keyword(s):  
Olfactory Bulb ◽  
Sensory Processing ◽  
Dopaminergic Neuron ◽  
Initial Segment ◽  
Mammalian Brain ◽  
Postnatal Life ◽  
Postnatal Neurogenesis ◽  
Functional Roles ◽  
Long Latency ◽  
Adult Born Neurons

AbstractMost neurogenesis in the mammalian brain is completed embryonically, but in certain areas the production of neurons continues throughout postnatal life. The functional properties of mature postnatally-generated neurons often match those of their embryonically-produced counterparts. However, we show here that in the olfactory bulb (OB), embryonic and postnatal neurogenesis produce functionally distinct subpopulations of dopaminergic (DA) neurons. We define two subclasses of OB DA neuron by the presence or absence of a key subcellular specialisation: the axon initial segment (AIS). Large AIS-positive axon-bearing DA neurons are exclusively produced during early embryonic stages, leaving small anaxonic AIS-negative cells as the only DA subtype generated via adult neurogenesis. These populations are functionally distinct: large DA cells are more excitable, yet display weaker and – for certain long-latency or inhibitory events – more broadly-tuned responses to odorant stimuli. Embryonic and postnatal neurogenesis can therefore generate distinct neuronal subclasses, placing important constraints on the functional roles of adult-born neurons in sensory processing.

scholarly journals Embryonic and postnatal neurogenesis produce functionally distinct subclasses of dopaminergic neuron

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Elisa Galliano ◽  
Eleonora Franzoni ◽  
Marine Breton ◽  
Annisa N Chand ◽  
Darren J Byrne ◽  
...  
Keyword(s):  
Olfactory Bulb ◽  
Sensory Processing ◽  
Dopaminergic Neuron ◽  
Initial Segment ◽  
Mammalian Brain ◽  
Postnatal Life ◽  
Postnatal Neurogenesis ◽  
Functional Roles ◽  
Long Latency ◽  
Adult Born Neurons

Most neurogenesis in the mammalian brain is completed embryonically, but in certain areas the production of neurons continues throughout postnatal life. The functional properties of mature postnatally generated neurons often match those of their embryonically produced counterparts. However, we show here that in the olfactory bulb (OB), embryonic and postnatal neurogenesis produce functionally distinct subpopulations of dopaminergic (DA) neurons. We define two subclasses of OB DA neuron by the presence or absence of a key subcellular specialisation: the axon initial segment (AIS). Large AIS-positive axon-bearing DA neurons are exclusively produced during early embryonic stages, leaving small anaxonic AIS-negative cells as the only DA subtype generated via adult neurogenesis. These populations are functionally distinct: large DA cells are more excitable, yet display weaker and – for certain long-latency or inhibitory events – more broadly tuned responses to odorant stimuli. Embryonic and postnatal neurogenesis can therefore generate distinct neuronal subclasses, placing important constraints on the functional roles of adult-born neurons in sensory processing.

scholarly journals The Role of Adult-Born Neurons in the Constantly Changing Olfactory Bulb Network

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Sarah Malvaut ◽  
Armen Saghatelyan
Keyword(s):  
Olfactory Bulb ◽  
Synapse Formation ◽  
Daily Basis ◽  
Mammalian Brain ◽  
Neuronal Progenitors ◽  
Neuronal Precursors ◽  
Continuous Progress ◽  
Adult Born Neurons ◽  
Migratory Stream

The adult mammalian brain is remarkably plastic and constantly undergoes structurofunctional modifications in response to environmental stimuli. In many regions plasticity is manifested by modifications in the efficacy of existing synaptic connections or synapse formation and elimination. In a few regions, however, plasticity is brought by the addition of new neurons that integrate into established neuronal networks. This type of neuronal plasticity is particularly prominent in the olfactory bulb (OB) where thousands of neuronal progenitors are produced on a daily basis in the subventricular zone (SVZ) and migrate along the rostral migratory stream (RMS) towards the OB. In the OB, these neuronal precursors differentiate into local interneurons, mature, and functionally integrate into the bulbar network by establishing output synapses with principal neurons. Despite continuous progress, it is still not well understood how normal functioning of the OB is preserved in the constantly remodelling bulbar network and what role adult-born neurons play in odor behaviour. In this review we will discuss different levels of morphofunctional plasticity effected by adult-born neurons and their functional role in the adult OB and also highlight the possibility that different subpopulations of adult-born cells may fulfill distinct functions in the OB neuronal network and odor behaviour.

scholarly journals Inhibitory circuits of the mammalian main olfactory bulb

2017 ◽  
Vol 118 (4) ◽  
pp. 2034-2051 ◽  
Author(s):  
Shawn D. Burton
Keyword(s):  
Olfactory Bulb ◽  
Sensory Processing ◽  
Granule Cells ◽  
Mammalian Brain ◽  
Gabaergic Interneuron ◽  
Main Olfactory Bulb ◽  
Firing Rates ◽  
Inhibitory Circuits ◽  
Inhibitory Mechanisms ◽  
Novel Model

Synaptic inhibition critically influences sensory processing throughout the mammalian brain, including the main olfactory bulb (MOB), the first station of sensory processing in the olfactory system. Decades of research across numerous laboratories have established a central role for granule cells (GCs), the most abundant GABAergic interneuron type in the MOB, in the precise regulation of principal mitral and tufted cell (M/TC) firing rates and synchrony through lateral and recurrent inhibitory mechanisms. In addition to GCs, however, the MOB contains a vast diversity of other GABAergic interneuron types, and recent findings suggest that, while fewer in number, these oft-ignored interneurons are just as important as GCs in shaping odor-evoked M/TC activity. Here I challenge the prevailing centrality of GCs. In this review, I first outline the specific properties of each GABAergic interneuron type in the rodent MOB, with particular emphasis placed on direct interneuron recordings and cell type-selective manipulations. On the basis of these properties, I then critically reevaluate the contribution of GCs vs. other interneuron types to the regulation of odor-evoked M/TC firing rates and synchrony via lateral, recurrent, and other inhibitory mechanisms. This analysis yields a novel model in which multiple interneuron types with distinct abundances, connectivity patterns, and physiologies complement one another to regulate M/TC activity and sensory processing.

scholarly journals Continuous Postnatal Neurogenesis Contributes to Formation of the Olfactory Bulb Neural Circuits and Flexible Olfactory Associative Learning

2014 ◽  
Vol 34 (17) ◽  
pp. 5788-5799 ◽  
Author(s):  
M. Sakamoto ◽  
N. Ieki ◽  
G. Miyoshi ◽  
D. Mochimaru ◽  
H. Miyachi ◽  
...  
Keyword(s):  
Olfactory Bulb ◽  
Associative Learning ◽  
Neural Circuits ◽  
Postnatal Neurogenesis

scholarly journals Adult-born neurons facilitate olfactory bulb pattern separation during task engagement

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Wankun L Li ◽  
Monica W Chu ◽  
An Wu ◽  
Yusuke Suzuki ◽  
Itaru Imayoshi ◽  
...  
Keyword(s):  
Olfactory Bulb ◽  
Adult Neurogenesis ◽  
Task Engagement ◽  
Pattern Separation ◽  
Inhibitory Neurons ◽  
Dependent Manner ◽  
Genetic Method ◽  
Two Photon ◽  
Passive Exposure ◽  
Adult Born Neurons

The rodent olfactory bulb incorporates thousands of newly generated inhibitory neurons daily throughout adulthood, but the role of adult neurogenesis in olfactory processing is not fully understood. Here we adopted a genetic method to inducibly suppress adult neurogenesis and investigated its effect on behavior and bulbar activity. Mice without young adult-born neurons (ABNs) showed normal ability in discriminating very different odorants but were impaired in fine discrimination. Furthermore, two-photon calcium imaging of mitral cells (MCs) revealed that the ensemble odor representations of similar odorants were more ambiguous in the ablation animals. This increased ambiguity was primarily due to a decrease in MC suppressive responses. Intriguingly, these deficits in MC encoding were only observed during task engagement but not passive exposure. Our results indicate that young olfactory ABNs are essential for the enhancement of MC pattern separation in a task engagement-dependent manner, potentially functioning as a gateway for top-down modulation.

scholarly journals Neuronal Activity-Dependent Control of Postnatal Neurogenesis and Gliogenesis

2018 ◽  
Vol 41 (1) ◽  
pp. 139-161 ◽  
Author(s):  
Ragnhildur T. Káradóttir ◽  
Chay T. Kuo
Keyword(s):  
Nervous System ◽  
Neuronal Activity ◽  
Molecular Mechanisms ◽  
Driving Forces ◽  
Nervous System Development ◽  
Current Evidence ◽  
Mammalian Brain ◽  
Postnatal Neurogenesis ◽  
Proliferation And Differentiation ◽  
Activity Dependent

The addition of new neurons and oligodendroglia in the postnatal and adult mammalian brain presents distinct forms of gray and white matter plasticity. Substantial effort has been devoted to understanding the cellular and molecular mechanisms controlling postnatal neurogenesis and gliogenesis, revealing important parallels to principles governing the embryonic stages. While during central nervous system development, scripted temporal and spatial patterns of neural and glial progenitor proliferation and differentiation are necessary to create the nervous system architecture, it remains unclear what driving forces maintain and sustain postnatal neural stem cell (NSC) and oligodendrocyte progenitor cell (OPC) production of new neurons and glia. In recent years, neuronal activity has been identified as an important modulator of these processes. Using the distinct properties of neurotransmitter ionotropic and metabotropic channels to signal downstream cellular events, NSCs and OPCs share common features in their readout of neuronal activity patterns. Here we review the current evidence for neuronal activity-dependent control of NSC/OPC proliferation and differentiation in the postnatal brain, highlight some potential mechanisms used by the two progenitor populations, and discuss future studies that might advance these research areas further.

New insights on the influence of free d-aspartate metabolism in the mammalian brain during prenatal and postnatal life

2020 ◽  
Vol 1868 (10) ◽  
pp. 140471 ◽  
Author(s):  
Francesco Errico ◽  
Mariella Cuomo ◽  
Nadia Canu ◽  
Viviana Caputo ◽  
Alessandro Usiello
Keyword(s):  
Mammalian Brain ◽  
Postnatal Life
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