scholarly journals Polarity and Competition in the Development of the Calyx of Held Terminal in the Medial Nucleus of the Trapezoid Body in the Mouse

2018 ◽  
Author(s):  
Paul Steven Holcomb
Author(s):  
Shobhana Sivaramakrishnan ◽  
Ashley Brandebura ◽  
Paul Holcomb ◽  
Daniel Heller ◽  
Douglas Kolson ◽  
...  

Bushy cells (BC) of the cochlear nucleus mono-innervate their target neuron, the principal cell of the medial nucleus of the trapezoid body (MNTB), via the calyx of Held (CH) terminal, which is a typically mammalian structure and perhaps the largest nerve terminal in the brain. CH:MNTB innervation has become an attractive model to study neural circuit formation because it forms quickly, passing through stages of competition in mice within 2–4 days. BCs innervate MNTB neurons by E17, but CHs do not begin to grow for another five days (P3). Progress has been made to identify molecular factors for axon guidance, CH growth, and physiological maturation of synaptic partners, but important details remain to be discovered. We summarize key events in CH formation and highlight unresolved issues in molecular and physiological signaling, roles for non-neural cells, and the nature of competition during the first postnatal week.


2010 ◽  
Vol 135 (6) ◽  
pp. 583-594 ◽  
Author(s):  
Daniel Reyes-Haro ◽  
Jochen Müller ◽  
Margarethe Boresch ◽  
Tatjyana Pivneva ◽  
Bruno Benedetti ◽  
...  

The calyx of Held (CoH) synapse serves as a model system to analyze basic mechanisms of synaptic transmission. Astrocyte processes are part of the synaptic structure and contact both pre- and postsynaptic membranes. In the medial nucleus of the trapezoid body (MNTB), midline stimulation evoked a current response that was not mediated by glutamate receptors or glutamate uptake, despite the fact that astrocytes express functional receptors and transporters. However, astrocytes showed spontaneous Ca2+ responses and neuronal slow inward currents (nSICs) were recorded in the postsynaptic principal neurons (PPNs) of the MNTB. These currents were correlated with astrocytic Ca2+ activity because dialysis of astrocytes with BAPTA abolished nSICs. Moreover, the frequency of these currents was increased when Ca2+ responses in astrocytes were elicited. NMDA antagonists selectively blocked nSICs while D-serine degradation significantly reduced NMDA-mediated currents. In contrast to previous studies in the hippocampus, these NMDA-mediated currents were rarely synchronized.


2004 ◽  
Vol 134 (2) ◽  
pp. 121-131 ◽  
Author(s):  
Jian-Yuan Sun ◽  
Xin-Sheng Wu ◽  
Wei Wu ◽  
Shan-Xue Jin ◽  
Anna Dondzillo ◽  
...  

2002 ◽  
Vol 22 (24) ◽  
pp. 10567-10579 ◽  
Author(s):  
Kurt Sätzler ◽  
Leander F. Söhl ◽  
Johann H. Bollmann ◽  
J. Gerard G. Borst ◽  
Michael Frotscher ◽  
...  

2004 ◽  
Vol 92 (1) ◽  
pp. 545-552 ◽  
Author(s):  
Jeremy B. Bergsman ◽  
Pietro De Camilli ◽  
David A. McCormick

The calyx of Held is a giant nerve terminal that forms a synapse directly onto the principal cells of the medial nucleus of the trapezoid body (MNTB) in the mammalian auditory brain stem. This central synapse, which is involved in sound localization, has become widely used for studying synaptic transmission. Anatomical studies of this nucleus have indicated that each principal cell is innervated by only one calyx. Here we use previously established electrophysiological criteria of excitatory postsynaptic current amplitude, kinetics, and transmitter type, as well as other characteristics commonly reported for this synapse, to examine the input properties of principal neurons. Our findings indicate that some principal cells receive more than one strong excitatory input. These inputs meet previously established electrophysiological criteria for identification as calyceal nerve terminals. Implications for the execution and analysis of experiments to avoid errors due to such multiple inputs are discussed.


Author(s):  
Leonard K. Kaczmarek

All neurons express a subset of over seventy genes encoding potassium channel subunits. These channels have been studied in auditory neurons, particularly in the medial nucleus of the trapezoid body. The amplitude and kinetics of various channels in these neurons can be modified by the auditory environment. It has been suggested that such modulation is an adaptation of neuronal firing patterns to specific patterns of auditory inputs. Alternatively, such modulation may allow a group of neurons, all expressing the same set of channels, to represent a variety of responses to the same pattern of incoming stimuli. Such diversity would ensure that a small number of genetically identical neurons could capture and encode many aspects of complex sound, including rapid changes in timing and amplitude. This review covers the modulation of ion channels in the medial nucleus of the trapezoid body and how it may maximize the extraction of auditory information.All neurons express a subset of over seventy genes encoding potassium channel subunits. These channels have been studied in auditory neurons, particularly in the medial nucleus of the trapezoid body. The amplitude and kinetics of various channels in these neurons can be modified by the auditory environment. It has been suggested that such modulation is an adaptation of neuronal firing patterns to specific patterns of auditory inputs. Alternatively, such modulation may allow a group of neurons, all expressing the same set of channels, to represent a variety of responses to the same pattern of incoming stimuli. Such diversity would ensure that a small number of genetically identical neurons could capture and encode many aspects of complex sound, including rapid changes in timing and amplitude. This review covers the modulation of ion channels in the medial nucleus of the trapezoid body and how it may maximize the extraction of auditory information.


2019 ◽  
Vol 597 (8) ◽  
pp. 2269-2295 ◽  
Author(s):  
Alexander U. Fischer ◽  
Nicolas I. C. Müller ◽  
Thomas Deller ◽  
Domenico Del Turco ◽  
Jonas O. Fisch ◽  
...  

2009 ◽  
Vol 134 (2) ◽  
pp. 115-127 ◽  
Author(s):  
Jochen Müller ◽  
Daniel Reyes-Haro ◽  
Tatjyana Pivneva ◽  
Christiane Nolte ◽  
Roland Schaette ◽  
...  

Glial cell processes are part of the synaptic structure and sense spillover of transmitter, while some glial cells can even receive direct synaptic input. Here, we report that a defined type of glial cell in the medial nucleus of the trapezoid body (MNTB) receives excitatory glutamatergic synaptic input from the calyx of Held (CoH). This giant glutamatergic terminal forms an axosomatic synapse with a single principal neuron located in the MNTB. The NG2 glia, as postsynaptic principal neurons, establish synapse-like structures with the CoH terminal. In contrast to the principal neurons, which are known to receive excitatory as well as inhibitory inputs, the NG2 glia receive mostly, if not exclusively, α-amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid receptor–mediated evoked and spontaneous synaptic input. Simultaneous recordings from neurons and NG2 glia indicate that they partially receive synchronized spontaneous input. This shows that an NG2+ glial cell and a postsynaptic neuron share presynaptic terminals.


2018 ◽  
Vol 24 ◽  
pp. 397-404 ◽  
Author(s):  
Jinsheng Dai ◽  
Jinfeng Liu ◽  
Mo Zhou ◽  
Wenjiao Wang ◽  
Zhi-Qing David Xu ◽  
...  

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