scholarly journals Self-sustained activity of low firing rate in balanced networks

2020 ◽  
Vol 537 ◽  
pp. 122671 ◽  
Author(s):  
F.S. Borges ◽  
P.R. Protachevicz ◽  
R.F.O. Pena ◽  
E.L. Lameu ◽  
G.S.V. Higa ◽  
...  
Keyword(s):  
Firing Rate ◽  
Sustained Activity ◽  
Balanced Networks

Contribution of GABA- and glycine-mediated inhibition to the monaural temporal response properties of neurons in the inferior colliculus

1996 ◽  
Vol 75 (2) ◽  
pp. 902-919 ◽  
Author(s):  
F. E. Le Beau ◽  
A. Rees ◽  
M. S. Malmierca
Keyword(s):  
Firing Rate ◽  
Inferior Colliculus ◽  
Discharge Rate ◽  
Glycine Receptor ◽  
Stimulus Onset ◽  
Sustained Response ◽  
Response Patterns ◽  
Gamma Aminobutyric Acid ◽  
Temporal Response ◽  
Sustained Activity

1. To determine the contribution of inhibition to the generation of the temporal response patterns of neurons in the inferior colliculus (IC), the effects of iontophoretically applied gamma-aminobutyric acid (GABA), glycine, and the GABAA and glycine receptor antagonists, bicuculline and strychnine were studied on 121 neurons in the IC of urethan-anesthetised guinea pig. 2. The neurons temporal discharge patterns were classified into six categories on the basis of their peristimulus time histograms (PSTHs). 1) Onset units fired at the stimulus onset and could be divided into two subtypes: narrow (1-2 spikes only) or broad (response lasting up to approximately 30 ms). 2) Pauser units had a precisely timed onset peak separated from a lower level of sustained activity by either a marked reduction or complete cessation of firing. 3) Chopper units had three or more clearly defined peaks near stimulus onset or evidence of regularly spaced peaks over the duration of the stimulus. 4) Onset-chopper units had three clearly defined peaks at onset but no sustained firing. 5) On-sustained units had a clearly defined single onset peak followed by a lower level of sustained activity. 6) Sustained units fired throughout the stimulus, but lacked an onset peak. 3. Iontophoretic application of GABA and glycine produced a dose-dependent reduction in firing rate in 76% (42/55) and 79% (11/14) of units, respectively. Application of bicuculline or strychnine increased the discharge rate in 91% (64/70) and 94% (16/17) of neurons, respectively. 4. The effects of bicuculline and strychnine on PSTH class were studied in detail on 70 neurons. Changes in discharge rate were accompanied by changes in PSTH in 49% (34/70) of neurons tested with bicuculline and 41% (7/17) tested with strychnine. Pauser units were the most affected with 69% changing their PSTH class, but some units in all PSTH classes, except the chopper group, exhibited changes in PSTH pattern after application of bicuculline. The majority of units (approximately 50%) that changed PSTH pattern in the presence of bicuculline became chopper units. Units of all PSTH classes could become choppers, but the proportion of units showing this change was dependent on the unit's control response pattern. All seven units that changed PSTH class with strychnine also became choppers. Changes in PSTH, including the appearance of a chopper pattern, did not depend on either a unit's control discharge rate or the magnitude of the change in discharge rate induced by the antagonists. 5. Bicuculline and strychnine had no significant effect on latency for units in the chopper, onset-chopper, onset, pauser, and on-sustained groups. A few sustained and unclassified units that had long predrug latencies did show marked reductions in latency when tested with bicuculline. 6. The majority of units did not fire spontaneously, and neither bicuculline or strychnine produced a significant increase in spontaneous rate. 7. In many units, the changes in firing rate did not occur equally over the duration of the response. Firing rates at the onset and in the last quarter of the sustained response were compared. Three effects of bicuculline and strychnine were observed. For 80% of units the largest change in firing rate occurred in the sustained response, while in 14% of units the change was greatest at onset.

scholarly journals Estimation of self-sustained activity produced by persistent inward currents using firing rate profiles of multiple motor units in humans

2020 ◽  
Vol 124 (1) ◽  
pp. 63-85 ◽  
Author(s):  
Babak Afsharipour ◽  
Nagib Manzur ◽  
Jennifer Duchcherer ◽  
Keith F. Fenrich ◽  
Christopher K. Thompson ◽  
...  
Keyword(s):  
Firing Rate ◽  
Motor Units ◽  
New Method ◽  
Persistent Inward Currents ◽  
Sustained Activity ◽  
Inward Currents ◽  
Synaptic Drive

A new method of estimating synaptic drive to multiple, simultaneously recorded motor units provides evidence that the portion of the depolarizing drive from persistent inward currents that contributes to self-sustained firing is similar across motoneurons of different sizes.

scholarly journals A deep convolutional visual encoding model of neuronal responses in the LGN

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Eslam Mounier ◽  
Bassem Abdullah ◽  
Hani Mahdi ◽  
Seif Eldawlatly
Keyword(s):  
Firing Rate ◽  
Visual Information ◽  
Visual Stimulation ◽  
Neuronal Population ◽  
Neuronal Firing ◽  
Electrode Arrays ◽  
Deep Convolutional Neural Networks ◽  
Firing Rates ◽  
Spatiotemporal Representation

AbstractThe Lateral Geniculate Nucleus (LGN) represents one of the major processing sites along the visual pathway. Despite its crucial role in processing visual information and its utility as one target for recently developed visual prostheses, it is much less studied compared to the retina and the visual cortex. In this paper, we introduce a deep learning encoder to predict LGN neuronal firing in response to different visual stimulation patterns. The encoder comprises a deep Convolutional Neural Network (CNN) that incorporates visual stimulus spatiotemporal representation in addition to LGN neuronal firing history to predict the response of LGN neurons. Extracellular activity was recorded in vivo using multi-electrode arrays from single units in the LGN in 12 anesthetized rats with a total neuronal population of 150 units. Neural activity was recorded in response to single-pixel, checkerboard and geometrical shapes visual stimulation patterns. Extracted firing rates and the corresponding stimulation patterns were used to train the model. The performance of the model was assessed using different testing data sets and different firing rate windows. An overall mean correlation coefficient between the actual and the predicted firing rates of 0.57 and 0.7 was achieved for the 10 ms and the 50 ms firing rate windows, respectively. Results demonstrate that the model is robust to variability in the spatiotemporal properties of the recorded neurons outperforming other examined models including the state-of-the-art Generalized Linear Model (GLM). The results indicate the potential of deep convolutional neural networks as viable models of LGN firing.

scholarly journals Hippocampal Interneurons are Required for Trace Eyeblink Conditioning in Mice

2021 ◽  
Author(s):  
Wei-Wei Zhang ◽  
Rong-Rong Li ◽  
Jie Zhang ◽  
Jie Yan ◽  
Qian-Hui Zhang ◽  
...  
Keyword(s):  
Eyeblink Conditioning ◽  
Pyramidal Cells ◽  
Conditioned Eyeblink ◽  
Cellular Mechanisms ◽  
Sustained Activity ◽  
Early Acquisition ◽  
Freely Moving ◽  
Trace Eyeblink Conditioning

AbstractWhile the hippocampus has been implicated in supporting the association among time-separated events, the underlying cellular mechanisms have not been fully clarified. Here, we combined in vivo multi-channel recording and optogenetics to investigate the activity of hippocampal interneurons in freely-moving mice performing a trace eyeblink conditioning (tEBC) task. We found that the hippocampal interneurons exhibited conditioned stimulus (CS)-evoked sustained activity, which predicted the performance of conditioned eyeblink responses (CRs) in the early acquisition of the tEBC. Consistent with this, greater proportions of hippocampal pyramidal cells showed CS-evoked decreased activity in the early acquisition of the tEBC. Moreover, optogenetic suppression of the sustained activity in hippocampal interneurons severely impaired acquisition of the tEBC. In contrast, suppression of the sustained activity of hippocampal interneurons had no effect on the performance of well-learned CRs. Our findings highlight the role of hippocampal interneurons in the tEBC, and point to a potential cellular mechanism subserving associative learning.

Identifying children at high risk for infection-related decompensation using a predictive emergency department-based electronic assessment tool

Diagnosis ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Robert J. Sepanski ◽  
Arno L. Zaritsky ◽  
Sandip A. Godambe
Keyword(s):  
Emergency Department ◽  
High Risk ◽  
Positive Predictive Value ◽  
Firing Rate ◽  
Predictive Value ◽  
Assessment Tool ◽  
Predictive Tool ◽  
High Severity ◽  
Electronic Assessment ◽  
Ed Visits

AbstractObjectivesElectronic alert systems to identify potential sepsis in children presenting to the emergency department (ED) often either alert too frequently or fail to detect earlier stages of decompensation where timely treatment might prevent serious outcomes.MethodsWe created a predictive tool that continuously monitors our hospital’s electronic health record during ED visits. The tool incorporates new standards for normal/abnormal vital signs based on data from ∼1.2 million children at 169 hospitals. Eighty-two gold standard (GS) sepsis cases arising within 48 h were identified through retrospective chart review of cases sampled from 35,586 ED visits during 2012 and 2014–2015. An additional 1,027 cases with high severity of illness (SOI) based on 3 M’s All Patient Refined – Diagnosis-Related Groups (APR-DRG) were identified from these and 26,026 additional visits during 2017. An iterative process assigned weights to main factors and interactions significantly associated with GS cases, creating an overall “score” that maximized the sensitivity for GS cases and positive predictive value for high SOI outcomes.ResultsTool implementation began August 2017; subsequent improvements resulted in 77% sensitivity for identifying GS sepsis within 48 h, 22.5% positive predictive value for major/extreme SOI outcomes, and 2% overall firing rate of ED patients. The incidence of high-severity outcomes increased rapidly with tool score. Admitted alert positive patients were hospitalized nearly twice as long as alert negative patients.ConclusionsOur ED-based electronic tool combines high sensitivity in predicting GS sepsis, high predictive value for physiologic decompensation, and a low firing rate. The tool can help optimize critical treatments for these high-risk children.

scholarly journals High-Frequency Synchronization Improves Firing Rate Contrast and Information Transmission Efficiency in E/I Neuronal Networks

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Fang Han ◽  
Zhijie Wang ◽  
Hong Fan ◽  
Yaopeng Zhang
Keyword(s):  
Information Transmission ◽  
Firing Rate ◽  
Contrast Enhancement ◽  
High Frequency ◽  
Functional Role ◽  
Neuronal Networks ◽  
Time Window ◽  
Frequency Synchronization ◽  
Neuronal System ◽  
Information Encoding

High-frequency synchronization has been found in many real neural systems and is confirmed by excitatory/inhibitory (E/I) network models. However, the functional role played by it remains elusive. In this paper, it is found that high-frequency synchronization in E/I neuronal networks could improve the firing rate contrast of the whole network, no matter if the network is fully connected or randomly connected, with noise or without noise. It is also found that the global firing rate contrast enhancement can prevent the number of spikes of the neurons measured within the limited time window from being confused by noise, thereby enhancing the information encoding efficiency (quantified by entropy theory here) of the neuronal system. The mechanism of firing rate contrast enhancement is also investigated. Our work implies a possible functional role in information transmission of high-frequency synchronization in neuronal systems.

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