Post-tetanic potentiation at the hippocampal mossy fiber–CA3 pyramidal neuron synapse shows a low induction threshold and is mediated by an increase in the readily releasable vesicle pool

2019 ◽  
Vol 7 (Suppl. 1) ◽  
pp. A1.7
Author(s):  
David Vandael
Keyword(s):  
Pyramidal Neuron ◽  
Mossy Fiber ◽  
Post Tetanic Potentiation ◽  
Vesicle Pool

scholarly journals Rapid and sustained homeostatic control of presynaptic exocytosis at a central synapse

2019 ◽  
Vol 116 (47) ◽  
pp. 23783-23789 ◽  
Author(s):  
Igor Delvendahl ◽  
Katarzyna Kita ◽  
Martin Müller
Keyword(s):  
Time Scales ◽  
Neural Circuit ◽  
Mossy Fiber ◽  
Pool Size ◽  
Homeostatic Plasticity ◽  
Experimental Conditions ◽  
Central Synapse ◽  
Circuit Function ◽  
Vesicle Pool ◽  
Activity Dependent

Animal behavior is remarkably robust despite constant changes in neural activity. Homeostatic plasticity stabilizes central nervous system (CNS) function on time scales of hours to days. If and how CNS function is stabilized on more rapid time scales remains unknown. Here, we discovered that mossy fiber synapses in the mouse cerebellum homeostatically control synaptic efficacy within minutes after pharmacological glutamate receptor impairment. This rapid form of homeostatic plasticity is expressed presynaptically. We show that modulations of readily releasable vesicle pool size and release probability normalize synaptic strength in a hierarchical fashion upon acute pharmacological and prolonged genetic receptor perturbation. Presynaptic membrane capacitance measurements directly demonstrate regulation of vesicle pool size upon receptor impairment. Moreover, presynaptic voltage-clamp analysis revealed increased Ca2+-current density under specific experimental conditions. Thus, homeostatic modulation of presynaptic exocytosis through specific mechanisms stabilizes synaptic transmission in a CNS circuit on time scales ranging from minutes to months. Rapid presynaptic homeostatic plasticity may ensure stable neural circuit function in light of rapid activity-dependent plasticity.

scholarly journals Depolarization-Induced Long-Term Depression at Hippocampal Mossy Fiber-CA3 Pyramidal Neuron Synapses

2003 ◽  
Vol 23 (30) ◽  
pp. 9786-9795 ◽  
Author(s):  
Saobo Lei ◽  
Kenneth A. Pelkey ◽  
Lisa Topolnik ◽  
Patrice Congar ◽  
Jean-Claude Lacaille ◽  
...  
Keyword(s):  
Pyramidal Neuron ◽  
Mossy Fiber ◽  
Long Term Depression

Voltage- and space-clamp errors associated with the measurement of electrotonically remote synaptic events

1993 ◽  
Vol 70 (2) ◽  
pp. 781-802 ◽  
Author(s):  
N. Spruston ◽  
D. B. Jaffe ◽  
S. H. Williams ◽  
D. Johnston
Keyword(s):  
Voltage Clamp ◽  
Pyramidal Neuron ◽  
Mossy Fiber ◽  
Reversal Potential ◽  
Realistic Model ◽  
Perforant Path ◽  
Synaptic Current ◽  
Synaptic Currents ◽  
Fast Kinetics ◽  
Minimal Reduction

1. The voltage- and space-clamp errors associated with the use of a somatic electrode to measure current from dendritic synapses are evaluated using both equivalent-cylinder and morphologically realistic models of neuronal dendritic trees. 2. As a first step toward understanding the properties of synaptic current distortion under voltage-clamp conditions, the attenuation of step and sinusoidal voltage changes are evaluated in equivalent cylinder models. Demonstration of the frequency-dependent attenuation of voltage in the cable is then used as a framework for understanding the distortion of synaptic currents generated at sites remote from the somatic recording electrode and measured in the voltage-clamp recording configuration. 3. Increases in specific membrane resistivity (Rm) are shown to reduce steady-state voltage attenuation, while producing only minimal reduction in attenuation of transient voltage changes. Experimental manipulations that increase Rm therefore improve the accuracy of estimates of reversal potential for electrotonically remote synapses, but do not significantly reduce the attenuation of peak current. In addition, increases in Rm have the effect of slowing the kinetics of poorly clamped synaptic currents. 4. The effects of the magnitude of the synaptic conductance and its kinetics on the measured synaptic currents are also examined and discussed. The error in estimating parameters from measured synaptic currents is greatest for synapses with fast kinetics and large conductances. 5. A morphologically realistic model of a CA3 pyramidal neuron is used to demonstrate the generality of the conclusions derived from equivalent cylinder models. The realistic model is also used to fit synaptic currents generated by stimulation of mossy fiber (MF) and commissural/associational (C/A) inputs to CA3 neurons and to estimate the amount of distortion of these measured currents. 6. Anatomic data from the CA3 pyramidal neuron model are used to construct a simplified two-cylinder CA3 model. This model is used to estimate the electrotonic distances of MF synapses (which are located proximal to the soma) and perforant path (PP) synapses (which are located at the distal ends of the apical dendrites) and the distortion of synaptic current parameters measured for these synapses. 7. Results from the equivalent-cylinder models, the morphological CA3 model, and the simplified CA3 model all indicate that the amount of distortion of synaptic currents increases steeply as a function of distance from the soma. MF synapses close to the soma are likely to be subject only to small space-clamp errors, whereas MF synapses farther from the soma are likely to be substantially attenuated.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Transsynaptic modulation of presynaptic short-term plasticity in hippocampal mossy fiber synapses

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
David Vandael ◽  
Yuji Okamoto ◽  
Peter Jonas
Keyword(s):  
Pyramidal Neurons ◽  
Mossy Fiber ◽  
Brain Slices ◽  
High Frequency Stimulation ◽  
Short Term Plasticity ◽  
Glutamate Signaling ◽  
Frequency Stimulation ◽  
Post Tetanic Potentiation ◽  
Mossy Fiber Synapse ◽  
Ca3 Neurons

AbstractThe hippocampal mossy fiber synapse is a key synapse of the trisynaptic circuit. Post-tetanic potentiation (PTP) is the most powerful form of plasticity at this synaptic connection. It is widely believed that mossy fiber PTP is an entirely presynaptic phenomenon, implying that PTP induction is input-specific, and requires neither activity of multiple inputs nor stimulation of postsynaptic neurons. To directly test cooperativity and associativity, we made paired recordings between single mossy fiber terminals and postsynaptic CA3 pyramidal neurons in rat brain slices. By stimulating non-overlapping mossy fiber inputs converging onto single CA3 neurons, we confirm that PTP is input-specific and non-cooperative. Unexpectedly, mossy fiber PTP exhibits anti-associative induction properties. EPSCs show only minimal PTP after combined pre- and postsynaptic high-frequency stimulation with intact postsynaptic Ca2+ signaling, but marked PTP in the absence of postsynaptic spiking and after suppression of postsynaptic Ca2+ signaling (10 mM EGTA). PTP is largely recovered by inhibitors of voltage-gated R- and L-type Ca2+ channels, group II mGluRs, and vacuolar-type H+-ATPase, suggesting the involvement of retrograde vesicular glutamate signaling. Transsynaptic regulation of PTP extends the repertoire of synaptic computations, implementing a brake on mossy fiber detonation and a “smart teacher” function of hippocampal mossy fiber synapses.

scholarly journals Short-Term Plasticity at Hippocampal Mossy Fiber Synapses Is Induced by Natural Activity Patterns and Associated with Vesicle Pool Engram Formation

Neuron ◽  
2020 ◽  
Vol 107 (3) ◽  
pp. 509-521.e7 ◽  
Author(s):  
David Vandael ◽  
Carolina Borges-Merjane ◽  
Xiaomin Zhang ◽  
Peter Jonas
Keyword(s):  
Mossy Fiber ◽  
Activity Patterns ◽  
Short Term ◽  
Natural Activity ◽  
Short Term Plasticity ◽  
Vesicle Pool
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