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.

scholarly journals Action potential counting at giant mossy fiber terminals gates information transfer in the hippocampus

2017 ◽  
Author(s):  
Simon Chamberland ◽  
Yulia Timofeeva ◽  
Alesya Evstratova ◽  
Kirill Volynski ◽  
Katalin Tóth
Keyword(s):  
Information Transfer ◽  
Pyramidal Neurons ◽  
Mossy Fiber ◽  
Mossy Fibers ◽  
Pyramidal Cells ◽  
Short Term ◽  
Ca3 Pyramidal Neurons ◽  
Presynaptic Calcium ◽  
Ca3 Pyramidal Cells ◽  
The Brain

AbstractHippocampal mossy fibers have long been recognized as conditional detonators owing to prominent short-term facilitation, but the patterns of activity required to fire postsynaptic CA3 pyramidal neurons remain poorly understood. We show that mossy fibers count the number of spikes to transmit information to CA3 pyramidal cells through a distinctive interplay between presynaptic calcium dynamics, buffering and vesicle replenishment. This identifies a previously unexplored information coding mechanism in the brain.

scholarly journals Increased Calbindin D28k Expression via Long-Term Alternate-Day Fasting Does Not Protect against Ischemia-Reperfusion Injury: A Focus on Delayed Neuronal Death, Gliosis and Immunoglobulin G Leakage

2021 ◽  
Vol 22 (2) ◽  
pp. 644
Author(s):  
Hyejin Sim ◽  
Tae-Kyeong Lee ◽  
Yeon Ho Yoo ◽  
Ji Hyeon Ahn ◽  
Dae Won Kim ◽  
...  
Keyword(s):  
Immunoglobulin G ◽  
Pyramidal Neurons ◽  
Short Term Memory ◽  
Forebrain Ischemia ◽  
Short Term ◽  
Term Memory ◽  
Transient Forebrain Ischemia ◽  
Ca1 Pyramidal Neurons ◽  
Ca1 Region ◽  
Calbindin D28k

Calbindin-D28k (CB), a calcium-binding protein, mediates diverse neuronal functions. In this study, adult gerbils were fed a normal diet (ND) or exposed to intermittent fasting (IF) for three months, and were randomly assigned to sham or ischemia operated groups. Ischemic injury was induced by transient forebrain ischemia for 5 min. Short-term memory was examined via passive avoidance test. CB expression was investigated in the Cornu Ammonis 1 (CA1) region of the hippocampus via western blot analysis and immunohistochemistry. Finally, histological analysis was used to assess neuroprotection and gliosis (microgliosis and astrogliosis) in the CA1 region. Short-term memory did not vary significantly between ischemic gerbils with IF and those exposed to ND. CB expression was increased significantly in the CA1 pyramidal neurons of ischemic gerbils with IF compared with that of gerbils fed ND. However, the CB expression was significantly decreased in ischemic gerbils with IF, similarly to that of ischemic gerbils exposed to ND. The CA1 pyramidal neurons were not protected from ischemic injury in both groups, and gliosis (astrogliosis and microgliosis) was gradually increased with time after ischemia. In addition, immunoglobulin G was leaked into the CA1 parenchyma from blood vessels and gradually increased with time after ischemic insult in both groups. Taken together, our study suggests that IF for three months increases CB expression in hippocampal CA1 pyramidal neurons; however, the CA1 pyramidal neurons are not protected from transient forebrain ischemia. This failure in neuroprotection may be attributed to disruption of the blood–brain barrier, which triggers gliosis after ischemic insults.

scholarly journals Effects of Presynaptic Calcium Stores on Short-Term Synaptic Plasticity

2012 ◽  
Vol 102 (3) ◽  
pp. 670a
Author(s):  
Suhita Nadkarni ◽  
Terence Sejnowski ◽  
Thomas Bartol ◽  
Charles Stevens ◽  
Herbert Levine ◽  
...  
Keyword(s):  
Synaptic Plasticity ◽  
Calcium Stores ◽  
Short Term ◽  
Presynaptic Calcium

scholarly journals Altered Short-Term Synaptic Plasticity in Mice Lacking the Metabotropic Glutamate Receptor mGlu7

2002 ◽  
Vol 2 ◽  
pp. 730-737 ◽  
Author(s):  
Trevor J. Bushell ◽  
Gilles Sansig ◽  
Valerie J. Collett ◽  
Herman van der Putten ◽  
Graham L. Collingridge
Keyword(s):  
Synaptic Plasticity ◽  
Molecular Mechanisms ◽  
Pyramidal Neurons ◽  
Metabotropic Glutamate Receptor ◽  
Long Term Potentiation ◽  
Short Term ◽  
Metabotropic Glutamate ◽  
Term Potentiation ◽  
Commissural Pathway ◽  
Frequency Facilitation

Eight subtypes of metabotropic glutamate (mGlu) receptors have been identified of which two, mGlu5 and mGlu7, are highly expressed at synapses made between CA3 and CA1 pyramidal neurons in the hippocampus. This input, the Schaffer collateral-commissural pathway, displays robust long-term potentiation (LTP), a process believed to utilise molecular mechanisms that are key processes involved in the synaptic basis of learning and memory. To investigate the possible function in LTP of mGlu7 receptors, a subtype for which no specific antagonists exist, we generated a mouse lacking this receptor, by homologous recombination. We found that LTP could be induced in mGlu7-/- mice and that once the potentiation had reached a stable level there was no difference in the magnitude of LTP between mGlu7-/- mice and their littermate controls. However, the initial decremental phase of LTP, known as short-term potentiation (STP), was greatly attenuated in the mGlu7-/- mouse. In addition, there was less frequency facilitation during, and less post-tetanic potentiation following, a high frequency train in the mGlu7-/- mouse. These results show that the absence of mGlu7 receptors results in alterations in short-term synaptic plasticity in the hippocampus.

Power-law correlations, related models for long-range dependence and their simulation

2000 ◽  
Vol 37 (04) ◽  
pp. 1104-1109 ◽  
Author(s):  
Tilmann Gneiting
Keyword(s):  
Long Range ◽  
Power Law ◽  
Long Memory ◽  
Stationary Time Series ◽  
Long Range Dependence ◽  
Short Term ◽  
Permissible Range ◽  
Simultaneous Fitting ◽  
Straightforward Proof

Martin and Walker ((1997) J. Appl. Prob. 34, 657–670) proposed the power-law ρ(v) = c|v|-β, |v| ≥ 1, as a correlation model for stationary time series with long-memory dependence. A straightforward proof of their conjecture on the permissible range of c is given, and various other models for long-range dependence are discussed. In particular, the Cauchy family ρ(v) = (1 + |v/c|α)-β/α allows for the simultaneous fitting of both the long-term and short-term correlation structure within a simple analytical model. The note closes with hints at the fast and exact simulation of fractional Gaussian noise and related processes.

Erratum to ‘Effects of Short-Term Random Noise Electrical Stimulation on Dissociated Pyramidal Neurons from the Cerebral Cortex’ [Neuroscience 404C (2019) 371–386]

Neuroscience ◽  
2019 ◽  
Vol 417 ◽  
pp. 107-108
Author(s):  
Leonardo Remedios ◽  
Pedro Mabil ◽  
Jorge Flores-Hernández ◽  
Oswaldo Torres-Ramírez ◽  
Nayeli Huidobro ◽  
...  
Keyword(s):  
Cerebral Cortex ◽  
Electrical Stimulation ◽  
Pyramidal Neurons ◽  
Random Noise ◽  
Short Term

From the Conference to the Classroom: Elevating Short-Term Professional Development for Lifelong Learning

2019 ◽  
Vol 33 (1) ◽  
pp. 24-28
Author(s):  
Justin J. West
Keyword(s):  
Professional Development ◽  
Lifelong Learning ◽  
Long Range ◽  
Professional Growth ◽  
Music Teachers ◽  
High Impact ◽  
Short Term

Short-term or “one shot” professional development experiences are sometimes deemed less effective because they lack mechanisms for deep and ongoing engagement. Using the music conference as an example, I outline a simple framework on how music teachers might nevertheless use short-term professional development experiences as an impetus for long-range and high-impact professional growth.

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