scholarly journals Non-associative Potentiation of Perisomatic Inhibition Alters the Temporal Coding of Neocortical Layer 5 Pyramidal Neurons

PLoS Biology ◽  
2014 ◽  
Vol 12 (7) ◽  
pp. e1001903 ◽  
Author(s):  
Joana Lourenço ◽  
Simone Pacioni ◽  
Nelson Rebola ◽  
Geeske M. van Woerden ◽  
Silvia Marinelli ◽  
...  
Keyword(s):  
Pyramidal Neurons ◽  
Temporal Coding ◽  
Perisomatic Inhibition

scholarly journals Basal tree complexity shapes functional pathways in the prefrontal cortex

2017 ◽  
Vol 118 (4) ◽  
pp. 1970-1983 ◽  
Author(s):  
Athanasia Papoutsi ◽  
George Kastellakis ◽  
Panayiota Poirazi
Keyword(s):  
Prefrontal Cortex ◽  
Pyramidal Neurons ◽  
Morphological Diversity ◽  
Temporal Coding ◽  
Coding Schemes ◽  
Functional Types ◽  
Tree Morphology ◽  
Wide Range ◽  
Ionic Mechanisms ◽  
Functional Pathways

While the morphology of basal dendritic trees in cortical pyramidal neurons varies, the functional implications of this diversity are just starting to emerge. In layer 5 pyramidal neurons of the prefrontal cortex, for example, increased basal tree complexity determines the recruitment of these neurons into functional circuits. Here, we use a modeling approach to investigate whether and how the morphology of the basal tree mediates the functional output of neurons. We implemented 57 basal tree morphologies of layer 5 prefrontal pyramidal neurons of the rat and identified morphological types that were characterized by different response features, forming distinct functional types. These types were robust to a wide range of manipulations (distribution of active ionic mechanisms, NMDA conductance, somatic and apical tree morphology, or the number of activated synapses) and supported different temporal coding schemes at both the single neuron and the microcircuit level. We predict that the basal tree morphological diversity among neurons of the same class mediates their segregation into distinct functional pathways. Extension of our approach/findings to other cortical areas and/or layers or under pathological conditions may provide a generalized role of the basal trees for neuronal function. NEW & NOTEWORTHY Our results suggest that the segregation of neurons to different functional types based on their basal tree morphology is in large part independent of the distribution of active ionic mechanisms, NMDA conductance, somatic and apical tree morphology, and the number of activated synapses; different functional types support distinct temporal coding schemes. This can be exploited to create networks with diverse coding characteristics, thus contributing to the functional heterogeneity within the same layer and area.

scholarly journals Resurgent Na+ currents promote ultrafast spiking in projection neurons that drive fine motor control

2021 ◽  
Author(s):  
Benjamin M. Zemel ◽  
Alexander A. Nevue ◽  
Andre Dagostin ◽  
Peter V. Lovell ◽  
Claudio V. Mello ◽  
...  
Keyword(s):  
Motor Neurons ◽  
High Frequency ◽  
Neuronal Excitability ◽  
Pyramidal Neurons ◽  
Vocal Learning ◽  
Temporal Coding ◽  
Fine Motor ◽  
Inactivation Kinetics ◽  
Projection Neurons ◽  
Upper Motor Neurons

AbstractThe underlying mechanisms that promote precise spiking in upper motor neurons controlling fine motor skills are not well understood. Here we report that projection neurons in the adult zebra finch song nucleus RA display: 1) robust high-frequency firing, 2) ultra-short half-width spike waveforms, 3) superfast Na+ current inactivation kinetics and 4) large resurgent Na+ currents (INaR). These spiking properties closely resemble those of specialized pyramidal neurons in mammalian motor cortex and are well suited for precise temporal coding. They emerge during the critical period for vocal learning in males but not females, coinciding with a complete switch of modulatory Na+ channel subunit expression from Navβ3 to Navβ4. Dynamic clamping and dialysis of Navβ4’s C-terminal peptide into juvenile RA neurons provide evidence that this subunit, and its associated INaR, promote neuronal excitability. We propose that Navβ4 underpins INaR that facilitates precise, prolonged, and reliable high-frequency firing in upper motor neurons.

scholarly journals Modulation of coordinated activity across cortical layers by plasticity of inhibitory synapses onto layer 5 pyramidal neurons

2019 ◽  
Author(s):  
Joana Lourenço ◽  
Angela Michela De Stasi ◽  
Charlotte Deleuze ◽  
Mathilde Bigot ◽  
Antonio Pazienti ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Information Transfer ◽  
Pyramidal Neurons ◽  
Long Term Potentiation ◽  
Network Activity ◽  
Temporal Association ◽  
Cortical Layers ◽  
Feed Forward ◽  
Sensory Evoked ◽  
Perisomatic Inhibition

AbstractIn the neocortex, synaptic inhibition shapes all forms of spontaneous and sensory-evoked activity. Importantly, inhibitory transmission is highly plastic, but the functional role of inhibitory synaptic plasticity is unknown. In the mouse barrel cortex, activation of layer 2/3 PNs elicited strong feed-forward perisomatic inhibition (FFI) onto layer 5 PNs. We found that FFI involving PV cells was strongly potentiated by postsynaptic PN burst firing. FFI plasticity modified PN excitation-to-inhibition (E/I) ratio, strongly modulated PN gain and altered information transfer across cortical layers. Moreover, our LTPi-inducing protocol modified the firing of layer 5 PNs and altered the temporal association of PN spikes to γ-oscillations both in vitro and in vivo. All these effects were captured by unbalancing the E/I ratio in a feed-forward inhibition circuit model. Altogether, our results indicate that activity-dependent modulation of perisomatic inhibitory strength effectively influences the participation of single principal cortical neurons to cognitive-relevant network activity.Impact StatementLong-term potentiation of feed-forward perisomatic inhibition effectively alters the computational properties of single layer 5 pyramidal neurons and their association to network activity.

scholarly journals Physiological noise optimizes multiplexed coding of vibrotactile-like signals in somatosensory cortex

2021 ◽  
Author(s):  
Mohammad Amin Kamaleddin ◽  
Aaron Shifman ◽  
Daniel MW Sigal ◽  
Steven A Prescott
Keyword(s):  
Somatosensory Cortex ◽  
Stimulus Intensity ◽  
High Frequency ◽  
Pyramidal Neurons ◽  
Phase Locking ◽  
Stimulus Frequency ◽  
Temporal Coding ◽  
Physiological Noise ◽  
Rate Coding

ABSTRACTNeurons can use different aspects of their spiking to simultaneously represent (multiplex) different features of a stimulus. For example, some pyramidal neurons in primary somatosensory cortex (S1) use the rate and timing of their spikes to respectively encode the intensity and frequency of vibrotactile stimuli. Doing so has several requirements. Because they fire at low rates, pyramidal neurons cannot entrain 1:1 with high-frequency (100-600 Hz) inputs and instead must skip (i.e. not respond to) some stimulus cycles. The proportion of skipped cycles must vary inversely with stimulus intensity for firing rate to encode stimulus intensity. Spikes must phase lock to the stimulus for spike times (intervals) to encode stimulus frequency but, in addition, skipping must occur irregularly to avoid aliasing. Using simulations and in vitro experiments in which S1 pyramidal neurons were stimulated with inputs emulating those induced by vibrotactile stimuli, we show that fewer cycles are skipped as stimulus intensity increases, as required for rate coding, and that physiological noise induces irregular skipping without disrupting phase locking, as required for temporal coding. This occurs because the reliability and precision of spikes evoked by small- amplitude, fast-onset signals are differentially sensitive to noise. Simulations confirmed that differences in stimulus intensity and frequency can be well discriminated based on differences in spike rate or timing, respectively, but only in the presence of noise. Our results show that multiplexed coding by S1 pyramidal neurons is facilitated rather than degraded by physiological levels of noise. In fact, multiplexing is optimal under physiologically noisy conditions.

Fading of the diaminobenzidine reaction product in the confocal scanning laser microscope

1989 ◽  
Vol 47 ◽  
pp. 146-147
Author(s):  
JS Deitch ◽  
KL Smith ◽  
JW Swann ◽  
JN Turner
Keyword(s):  
Pyramidal Neurons ◽  
Light And Electron Microscopy ◽  
Scanning Laser ◽  
Laser Exposure ◽  
Confocal Scanning Laser Microscope ◽  
Fluorescent Markers ◽  
Before And After ◽  
Staining Protocol ◽  
Confocal Scanning ◽  
Confocal Scanning Laser

Neurons labeled with horseradish peroxidase and reacted with diaminobenzidine (DAB) can be imaged using a confocal scanning laser microscope (CSLM) in the reflection mode. In contrast to fluorescent markers, the DAB reaction product is thought to be stable and can be observed by both light and electron microscopy. We have investigated the sensitivity of the DAB reaction product to laser irradiation, and present the spectrophotometric properties of DAB before and after exposure in the CSLM.Pyramidal neurons in slices of rat hippocampus were injected with biocytin (a biotin-lysine complex), fixed overnight in 4% paraformaldehyde, and vibratome sectioned at 75 μm. Biocytin was detected with avidin-HRP (1:200) in 0.5% Triton X-100, incubated in DAB (0.5 mg/ml) with or without 0.04% nickel ammonium sulfate (Ni), dehydrated, and imaged in a Bio Rad MRC-500 CSLM with an argon ion laser (488 and 514 nm). Spectrophotometric measurements of the soma were made on a Zeiss microspectrophotometer, as a function of laser exposure (100-1000 scans) and staining protocol.

Temporal Coding in Realistic Neural Networks

1995 ◽  
Vol 5 (10) ◽  
pp. 1367-1374
Author(s):  
S. M. Gerasyuta ◽  
D. V. Ivanov
Keyword(s):  
Neural Networks ◽  
Temporal Coding
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