scholarly journals Cortical ChAT+ neurons co-transmit acetylcholine and GABA in a target- and brain-region-specific manner

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Adam J Granger ◽  
Wengang Wang ◽  
Keiramarie Robertson ◽  
Mahmoud El-Rifai ◽  
Andrea F Zanello ◽  
...  
Keyword(s):  
Synaptic Connectivity ◽  
Local Source ◽  
Inhibitory Interneurons ◽  
Target Neuron ◽  
Mouse Cerebral Cortex ◽  
Specific Manner ◽  
Release Of Acetylcholine ◽  
Differential Transmission ◽  
Sparse Population ◽  
Postsynaptic Target

The mouse cerebral cortex contains neurons that express choline acetyltransferase (ChAT) and are a potential local source of acetylcholine. However, the neurotransmitters released by cortical ChAT+ neurons and their synaptic connectivity are unknown. We show that the nearly all cortical ChAT+ neurons in mice are specialized VIP+ interneurons that release GABA strongly onto other inhibitory interneurons and acetylcholine sparsely onto layer 1 interneurons and other VIP+/ChAT+ interneurons. This differential transmission of ACh and GABA based on the postsynaptic target neuron is reflected in VIP+/ChAT+ interneuron pre-synaptic terminals, as quantitative molecular analysis shows that only a subset of these are specialized to release acetylcholine. In addition, we identify a separate, sparse population of non-VIP ChAT+ neurons in the medial prefrontal cortex with a distinct developmental origin that robustly release acetylcholine in layer 1. These results demonstrate both cortex-region heterogeneity in cortical ChAT+ interneurons and target-specific co-release of acetylcholine and GABA.

scholarly journals Cortical ChAT+ neurons co-transmit acetylcholine and GABA in a target- and brain-region specific manner

2020 ◽  
Author(s):  
Adam J Granger ◽  
Wengang Wang ◽  
Keiramarie Robertson ◽  
Mahmoud El-Rifai ◽  
Andrea Zanello ◽  
...  
Keyword(s):  
Cerebral Cortex ◽  
Synaptic Connectivity ◽  
Local Source ◽  
Inhibitory Interneurons ◽  
Target Neuron ◽  
Specific Manner ◽  
Release Of Acetylcholine ◽  
Differential Transmission ◽  
Sparse Population ◽  
Postsynaptic Target

AbstractThe cerebral cortex contains neurons that express choline acetyltransferase (ChAT) and are a potential local source of acetylcholine. However, the neurotransmitters released by cortical ChAT+ neurons and their synaptic connectivity are unknown. We show that the nearly all cortical ChAT+ neurons are specialized VIP+ interneurons that release GABA strongly onto other inhibitory interneurons and acetylcholine sparsely onto layer 1 interneurons and other VIP+/ChAT+ interneurons. This differential transmission of ACh and GABA based on the postsynaptic target neuron is reflected in VIP+/ChAT+ interneuron pre-synaptic terminals, as quantitative molecular analysis shows that only a subset of these are specialized to release acetylcholine. In addition, we identify a separate, sparse population of non-VIP ChAT+ neurons in the medial prefrontal cortex with a distinct developmental origin that robustly release acetylcholine in layer 1. These results demonstrate both cortex-region heterogeneity in cortical ChAT+ interneurons and target-specific co-release of acetylcholine and GABA.

scholarly journals Diversity and Function of Somatostatin-Expressing Interneurons in the Cerebral Cortex

2019 ◽  
Vol 20 (12) ◽  
pp. 2952 ◽  
Author(s):  
Therese Riedemann
Keyword(s):  
Major Depressive Disorder ◽  
Cerebral Cortex ◽  
Depressive Disorder ◽  
Neurological Disorders ◽  
Synaptic Connectivity ◽  
Inhibitory Interneurons ◽  
Cortical Circuits ◽  
Major Depressive ◽  
Neuron Population ◽  
And Function

Inhibitory interneurons make up around 10–20% of the total neuron population in the cerebral cortex. A hallmark of inhibitory interneurons is their remarkable diversity in terms of morphology, synaptic connectivity, electrophysiological and neurochemical properties. It is generally understood that there are three distinct and non-overlapping interneuron classes in the mouse neocortex, namely, parvalbumin-expressing, 5-HT3A receptor-expressing and somatostatin-expressing interneuron classes. Each class is, in turn, composed of a multitude of subclasses, resulting in a growing number of interneuron classes and subclasses. In this review, I will focus on the diversity of somatostatin-expressing interneurons (SOM+ INs) in the cerebral cortex and elucidate their function in cortical circuits. I will then discuss pathological consequences of a malfunctioning of SOM+ INs in neurological disorders such as major depressive disorder, and present future avenues in SOM research and brain pathologies.

Fhod3 Controls the Dendritic Spine Morphology of Specific Subpopulations of Pyramidal Neurons in the Mouse Cerebral Cortex

2020 ◽  
Author(s):  
Hikmawan Wahyu Sulistomo ◽  
Takayuki Nemoto ◽  
Yohko Kage ◽  
Hajime Fujii ◽  
Taku Uchida ◽  
...  
Keyword(s):  
Dendritic Spines ◽  
Dendritic Spine ◽  
Pyramidal Neurons ◽  
Cell Type ◽  
Spine Morphology ◽  
Mouse Cerebral Cortex ◽  
Specific Manner ◽  
Cell Type Specific ◽  
The Brain ◽  
Spine Morphogenesis

Abstract Changes in the shape and size of the dendritic spines are critical for synaptic transmission. These morphological changes depend on dynamic assembly of the actin cytoskeleton and occur differently in various types of neurons. However, how the actin dynamics are regulated in a neuronal cell type-specific manner remains largely unknown. We show that Fhod3, a member of the formin family proteins that mediate F-actin assembly, controls the dendritic spine morphogenesis of specific subpopulations of cerebrocortical pyramidal neurons. Fhod3 is expressed specifically in excitatory pyramidal neurons within layers II/III and V of restricted areas of the mouse cerebral cortex. Immunohistochemical and biochemical analyses revealed the accumulation of Fhod3 in postsynaptic spines. Although targeted deletion of Fhod3 in the brain did not lead to any defects in the gross or histological appearance of the brain, the dendritic spines in pyramidal neurons within presumptive Fhod3-positive areas were morphologically abnormal. In primary cultures prepared from the Fhod3-depleted cortex, defects in spine morphology were only detected in Fhod3 promoter-active cells, a small population of pyramidal neurons, and not in Fhod3 promoter-negative pyramidal neurons. Thus, Fhod3 plays a crucial role in dendritic spine morphogenesis only in a specific population of pyramidal neurons in a cell type-specific manner.

scholarly journals Cerebellar connectivity maps embody individual adaptive behavior

2021 ◽  
Author(s):  
Ludovic Spaeth ◽  
Jyotika Bahuguna ◽  
Theo Gagneux ◽  
Kevin Dorgans ◽  
Izumi Sugihara ◽  
...  
Keyword(s):  
Critical Period ◽  
Spatial Organization ◽  
Granule Cells ◽  
Functional Organization ◽  
Motor Adaptation ◽  
Synaptic Connectivity ◽  
General Motor ◽  
Behavioral Features ◽  
Specific Manner ◽  
Context Specific

AbstractFrom planification to execution, cerebellar microcircuits encode different features of skilled movements. However, it is unknown whether cerebellar synaptic connectivity maps encode movement features in a motor context specific manner. Here we investigated the spatial organization of excitatory synaptic connectivity in mice cerebellar cortex in different locomotor contexts: during development and in normal, trained or altered locomotor conditions. We combined optical, electrophysiological and graph modelling approaches to describe synaptic connectivity between granule cells (GCs) and Purkinje cells (PCs). Synaptic map maturation during development revealed a critical period in juvenile animals before the establishment of a stereotyped functional organization in adults. However, different locomotor conditions lead to specific GC-PC connectivity maps in PCs. Ultimately, we demonstrated that the variability in connectivity maps directly accounts for individual specific behavioral features of mice locomotion, suggesting that GC-PC networks encode a general motor context as well as individual specific internal models underlying motor adaptation.

scholarly journals Short-term dynamics of long-range corticocortical synapses revealed by selective optical stimulation

2021 ◽  
Author(s):  
Luis E Martinetti ◽  
Kelly E Bonekamp ◽  
Dawn M Autio ◽  
Shane R Crandall
Keyword(s):  
Long Range ◽  
Pyramidal Neurons ◽  
Short Term ◽  
Dynamic Regulation ◽  
Secondary Somatosensory Cortex ◽  
Target Neuron ◽  
Cellular Excitability ◽  
Presynaptic Calcium ◽  
Corticocortical Projections ◽  
Postsynaptic Target

Synapses are continually regulated by their own activity. In the neocortex, direct interactions between cortical areas play a central role in cognitive function, but the dynamic regulation of these long-range corticocortical synapses by activity and their impact on a postsynaptic target neuron is unclear. Here, we use an optogenetic strategy to study the connections between mouse somatosensory and motor cortex. We found that short-term synaptic facilitation was strong in both corticocortical synapses, resulting in far more sustained responses than local intra-cortical and thalamocortical connections. This facilitation was dependent on the presynaptic calcium sensor synaptotagmin-7 and altered by several optogenetic approaches. Recordings revealed that during repetitive activation, the short-term dynamics of corticocortical synapses enhanced the excitability of layer 2/3 pyramidal neurons, increasing the probability of spiking with activity. Furthermore, the properties of the connections linking primary with secondary somatosensory cortex resemble those between somatosensory-motor areas. These results reveal a synaptic mechanism by which corticocortical projections may mediate specific changes in cellular excitability over relatively extended periods.

Computer Reconstruction of the Cellular Architecture of the Daphnia Magna Optic Ganglion

1975 ◽  
Vol 33 ◽  
pp. 284-285
Author(s):  
E. R. Macagno ◽  
C. Levinthal
Keyword(s):  
Daphnia Magna ◽  
Genetic Background ◽  
Compound Eye ◽  
Synaptic Connectivity ◽  
Serial Sections ◽  
Cross Sectional ◽  
Small Crustacean ◽  
Optic Ganglion ◽  
Structural Invariance ◽  
High Degree

The optic ganglion of Daphnia Magna, a small crustacean that reproduces parthenogenetically contains about three hundred neurons: 110 neurons in the Lamina or anterior region and about 190 neurons in the Medulla or posterior region. The ganglion lies in the midplane of the organism and shows a high degree of left-right symmetry in its structures. The Lamina neurons form the first projection of the visual output from 176 retinula cells in the compound eye. In order to answer questions about structural invariance under constant genetic background, we have begun to reconstruct in detail the morphology and synaptic connectivity of various neurons in this ganglion from electron micrographs of serial sections (1). The ganglion is sectioned in a dorso-ventra1 direction so as to minimize the cross-sectional area photographed in each section. This area is about 60 μm x 120 μm, and hence most of the ganglion fit in a single 70 mm micrograph at the lowest magnification (685x) available on our Zeiss EM9-S.

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