scholarly journals Short-term plasticity regulates the excitation/inhibition ratio and the temporal window for spike integration in CA1 pyramidal cells

2015 ◽  
Vol 41 (11) ◽  
pp. 1402-1415 ◽  
Author(s):  
Aundrea F. Bartley ◽  
Lynn E. Dobrunz
Keyword(s):  
Pyramidal Cells ◽  
Short Term ◽  
Temporal Window ◽  
Short Term Plasticity ◽  
Inhibition Ratio ◽  
Ca1 Pyramidal Cells

scholarly journals A novel short-term plasticity of intrinsic excitability in the hippocampal CA1 pyramidal cells

2014 ◽  
Vol 592 (13) ◽  
pp. 2845-2864 ◽  
Author(s):  
A. Sánchez-Aguilera ◽  
J. L. Sánchez-Alonso ◽  
M. A. Vicente-Torres ◽  
A. Colino
Keyword(s):  
Pyramidal Cells ◽  
Intrinsic Excitability ◽  
Short Term ◽  
Short Term Plasticity ◽  
Ca1 Pyramidal Cells ◽  
Hippocampal Ca1

Hippocampus Retains the Periodicity of Gamma Stimulation In Vivo

2002 ◽  
Vol 88 (5) ◽  
pp. 2349-2354 ◽  
Author(s):  
J. E. Mikkonen ◽  
T. Grönfors ◽  
J. J. Chrobak ◽  
M. Penttonen
Keyword(s):  
Information Acquisition ◽  
Pyramidal Cells ◽  
Gamma Oscillations ◽  
Short Term ◽  
Ca1 Pyramidal Cells ◽  
State Dependent ◽  
Hippocampal Ca1 ◽  
Oscillatory Rhythms ◽  
The Brain

Several behavioral state dependent oscillatory rhythms have been identified in the brain. Of these neuronal rhythms, gamma (20–70 Hz) oscillations are prominent in the activated brain and are associated with various behavioral functions ranging from sensory binding to memory. Hippocampal gamma oscillations represent a widely studied band of frequencies co-occurring with information acquisition. However, induction of specific gamma frequencies within the hippocampal neuronal network has not been satisfactorily established. Using both in vivo intracellular and extracellular recordings from anesthetized rats, we show that hippocampal CA1 pyramidal cells can discharge at frequencies determined by the preceding gamma stimulation, provided that the gamma is introduced in theta cycles, as occurs in vivo. The dynamic short-term alterations in the oscillatory discharge described in this paper may serve as a coding mechanism in cortical neuronal networks.

Multiple Forms of Short-Term Plasticity at Excitatory Synapses in Rat Medial Prefrontal Cortex

2000 ◽  
Vol 83 (5) ◽  
pp. 3031-3041 ◽  
Author(s):  
Chris M. Hempel ◽  
Kenichi H. Hartman ◽  
X.-J. Wang ◽  
Gina G. Turrigiano ◽  
Sacha B. Nelson
Keyword(s):  
Prefrontal Cortex ◽  
Medial Prefrontal Cortex ◽  
Dynamic Properties ◽  
Specific Property ◽  
Pyramidal Cells ◽  
Excitatory Synapses ◽  
Short Term ◽  
Short Term Plasticity ◽  
Layer V

Short-term synaptic plasticity, in particular short-term depression and facilitation, strongly influences neuronal activity in cerebral cortical circuits. We investigated short-term plasticity at excitatory synapses onto layer V pyramidal cells in the rat medial prefrontal cortex, a region whose synaptic dynamic properties have not been systematically examined. Using intracellular and extracellular recordings of synaptic responses evoked by stimulation in layers II/III in vitro, we found that short-term depression and short-term facilitation are similar to those described previously in other regions of the cortex. In additition, synapses in the prefrontal cortex prominently express augmentation, a longer lasting form of short-term synaptic enhancement. This consists of a 40–60% enhancement of synaptic transmission which lasts seconds to minutes and which can be induced by stimulus trains of moderate duration and frequency. Synapses onto layer III neurons in the primary visual cortex express substantially less augmentation, indicating that this is a synapse-specific property. Intracellular recordings from connected pairs of layer V pyramidal cells in the prefrontal cortex suggest that augmentation is a property of individual synapses that does not require activation of multiple synaptic inputs or neuromodulatory fibers. We propose that synaptic augmentation could function to enhance the ability of a neuronal circuit to sustain persistent activity after a transient stimulus. This idea is explored using a computer simulation of a simplified recurrent cortical network.

Spontaneous Slow Oscillations and Sequential Patterns Due to Short-Term Plasticity in a Model of the Cortex

2013 ◽  
Vol 25 (12) ◽  
pp. 3131-3182 ◽  
Author(s):  
Timothée Leleu ◽  
Kazuyuki Aihara
Keyword(s):  
Mean Field ◽  
Low Frequency ◽  
Pyramidal Cells ◽  
Field Approximation ◽  
Mean Field Approximation ◽  
Cortical Column ◽  
Short Term ◽  
Slow Oscillations ◽  
Short Term Plasticity ◽  
Dynamic Synapses

We study a realistic model of a cortical column taking into account short-term plasticity between pyramidal cells and interneurons. The simulation of leaky integrate-and-fire neurons shows that low-frequency oscillations emerge spontaneously as a result of intrinsic network properties. These oscillations are composed of prolonged phases of high and low activity reminiscent of cortical up and down states, respectively. We simplify the description of the network activity by using a mean field approximation and reduce the system to two slow variables exhibiting some relaxation oscillations. We identify two types of slow oscillations. When the combination of dynamic synapses between pyramidal cells and those between interneurons accounts for the generation of these slow oscillations, the end of the up phase is characterized by asynchronous fluctuations of the membrane potentials. When the slow oscillations are mainly driven by the dynamic synapses between interneurons, the network exhibits fluctuations of membrane potentials, which are more synchronous at the end than at the beginning of the up phase. Additionally, finite size effect and slow synaptic currents can modify the irregularity and frequency, respectively, of these oscillations. Finally, we consider possible roles of a slow oscillatory input modeling long-range interactions in the brain. Spontaneous slow oscillations of local networks are modulated by the oscillatory input, which induces, notably, synchronization, subharmonic synchronization, and chaotic relaxation oscillations in the mean field approximation. In the case of forced oscillations, the slow population-averaged activity of leaky integrate-and-fire neurons can have both deterministic and stochastic temporal features. We discuss the possibility that long-range connectivity controls the emergence of slow sequential patterns in local populations due to the tendency of a cortical column to oscillate at low frequency.

scholarly journals Plasticity-dependent, full detonation at hippocampal mossy fiber–CA3 pyramidal neuron synapses

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Nicholas P Vyleta ◽  
Carolina Borges-Merjane ◽  
Peter Jonas
Keyword(s):  
Granule Cells ◽  
Mossy Fiber ◽  
Brain Slices ◽  
Pyramidal Cells ◽  
Short Term ◽  
Short Term Plasticity ◽  
Cell Network ◽  
Post Tetanic Potentiation ◽  
Ca3 Pyramidal Cells ◽  
Ca3 Neurons

Mossy fiber synapses on CA3 pyramidal cells are 'conditional detonators' that reliably discharge postsynaptic targets. The 'conditional' nature implies that burst activity in dentate gyrus granule cells is required for detonation. Whether single unitary excitatory postsynaptic potentials (EPSPs) trigger spikes in CA3 neurons remains unknown. Mossy fiber synapses exhibit both pronounced short-term facilitation and uniquely large post-tetanic potentiation (PTP). We tested whether PTP could convert mossy fiber synapses from subdetonator into detonator mode, using a recently developed method to selectively and noninvasively stimulate individual presynaptic terminals in rat brain slices. Unitary EPSPs failed to initiate a spike in CA3 neurons under control conditions, but reliably discharged them after induction of presynaptic short-term plasticity. Remarkably, PTP switched mossy fiber synapses into full detonators for tens of seconds. Plasticity-dependent detonation may be critical for efficient coding, storage, and recall of information in the granule cell–CA3 cell network.

Time Window from Visual Images to Visual Short-Term Memory: Consolidation or Integration?

2004 ◽  
Vol 51 (1) ◽  
pp. 45-51 ◽  
Author(s):  
Yuhong Jiang
Keyword(s):  
Short Term Memory ◽  
Time Window ◽  
Short Interval ◽  
Visual Images ◽  
Short Term ◽  
Temporal Window ◽  
Term Memory ◽  
Visual Short Term Memory ◽  
Probe Task ◽  
Long Time

Abstract. When two dot arrays are briefly presented, separated by a short interval of time, visual short-term memory of the first array is disrupted if the interval between arrays is shorter than 1300-1500 ms ( Brockmole, Wang, & Irwin, 2002 ). Here we investigated whether such a time window was triggered by the necessity to integrate arrays. Using a probe task we removed the need for integration but retained the requirement to represent the images. We found that a long time window was needed for performance to reach asymptote even when integration across images was not required. Furthermore, such window was lengthened if subjects had to remember the locations of the second array, but not if they only conducted a visual search among it. We suggest that a temporal window is required for consolidation of the first array, which is vulnerable to disruption by subsequent images that also need to be memorized.

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