Role of Precise Spike Timing in Coding of Dynamic Vibrissa Stimuli in Somatosensory Thalamus

2007 ◽  
Vol 98 (4) ◽  
pp. 1871-1882 ◽  
Author(s):  
Marcelo A. Montemurro ◽  
Stefano Panzeri ◽  
Miguel Maravall ◽  
Andrea Alenda ◽  
Michael R. Bale ◽  
...  
Keyword(s):  
Firing Rate ◽  
Barrel Cortex ◽  
Neural Code ◽  
Spike Timing ◽  
Unit Recording ◽  
Temporal Correlations ◽  
Independent Information ◽  
Temporally Correlated ◽  
Spike Patterns

Rats discriminate texture by whisking their vibrissae across the surfaces of objects. This process induces corresponding vibrissa vibrations, which must be accurately represented by neurons in the somatosensory pathway. In this study, we investigated the neural code for vibrissa motion in the ventroposterior medial (VPm) nucleus of the thalamus by single-unit recording. We found that neurons conveyed a great deal of information (up to 77.9 bits/s) about vibrissa dynamics. The key was precise spike timing, which typically varied by less than a millisecond from trial to trial. The neural code was sparse, the average spike being remarkably informative (5.8 bits/spike). This implies that as few as four VPm spikes, coding independent information, might reliably differentiate between 106 textures. To probe the mechanism of information transmission, we compared the role of time-varying firing rate to that of temporally correlated spike patterns in two ways: 93.9% of the information encoded by a neuron could be accounted for by a hypothetical neuron with the same time-dependent firing rate but no correlations between spikes; moreover, ≥93.4% of the information in the spike trains could be decoded even if temporal correlations were ignored. Taken together, these results suggest that the essence of the VPm code for vibrissa motion is firing rate modulation on a submillisecond timescale. The significance of such a code may be that it enables a small number of neurons, firing only few spikes, to convey distinctions between very many different textures to the barrel cortex.

scholarly journals Sparse bursts optimize information transmission in a multiplexed neural code

2018 ◽  
Vol 115 (27) ◽  
pp. E6329-E6338 ◽  
Author(s):  
Richard Naud ◽  
Henning Sprekeler
Keyword(s):  
Firing Rate ◽  
Cortical Neurons ◽  
Neural Code ◽  
Spike Timing ◽  
Neural Ensemble ◽  
Multiple Input ◽  
Cortical Hierarchy ◽  
Connectivity Patterns ◽  
Rate Coding

Many cortical neurons combine the information ascending and descending the cortical hierarchy. In the classical view, this information is combined nonlinearly to give rise to a single firing-rate output, which collapses all input streams into one. We analyze the extent to which neurons can simultaneously represent multiple input streams by using a code that distinguishes spike timing patterns at the level of a neural ensemble. Using computational simulations constrained by experimental data, we show that cortical neurons are well suited to generate such multiplexing. Interestingly, this neural code maximizes information for short and sparse bursts, a regime consistent with in vivo recordings. Neurons can also demultiplex this information, using specific connectivity patterns. The anatomy of the adult mammalian cortex suggests that these connectivity patterns are used by the nervous system to maintain sparse bursting and optimal multiplexing. Contrary to firing-rate coding, our findings indicate that the physiology and anatomy of the cortex may be interpreted as optimizing the transmission of multiple independent signals to different targets.

scholarly journals Differential Effects of the Lateral Hypothalamus Lesion as an Origin of Orexin and Blockade of Orexin-1 Receptor in the Orbitoftontal Cortex and Anterior Cingulate Cortex on Their Neuronal Activity

2021 ◽  
Vol 0 (0) ◽  
pp. 1-29
Author(s):  
Sara Karimi ◽  
◽  
Mohammad Ismail Zibaii ◽  
Gholam Ali Hamidi ◽  
Abbas Haghparast ◽  
...  
Keyword(s):  
Firing Rate ◽  
Anterior Cingulate Cortex ◽  
Cognitive Processes ◽  
Lateral Hypothalamus ◽  
Cingulate Cortex ◽  
Anterior Cingulate ◽  
Unit Recording ◽  
Baseline Recording

Several studies revealed that orexins may take part in the regulation of the different forms of affective and cognitive processes during wakefulness. The orbitofrontal cortex (OFC) and anterior cingulate cortex (ACC) as an important part of the prefrontal cortex (PFC) have a crucial role in cognitive processes such as reward and decision-making and has a high density of orexin receptor type 1 (OX1Rs). In the present study, to find out the role of OX1Rs in the OFC neurons firing rate, the OX1Rs were inhibited in this area after a10-min baseline recording. In the second part, the lateral hypothalamus (LH) as the main source of orexinergic neurons was inhibited and its effect on the firing rate and activity pattern of the ACC or OFC neurons were detected by using single-unit recording technique in the rats. Results showed that blockade of OX1Rs in the OFC could excite 8 and inhibit 1 neuron out of 11. Besides, the blockade of OX1Rs in the ACC could excite 6 and inhibit 3 neurons out of 10. Also, LH inactivation excited 5 out of 12 neurons and inhibited 6 neurons in the ACC. It excited 8 and inhibited 6 neurons out of 14 in the OFC. These data suggested that blockade of the OX1Rs excited 72% of the neurons, but LH inactivation had an exciting effect on just 50% of neurons in two main subregions of PFC. It seems that the PFC neurons receive the orexinergic inputs from the LH and indirectly from other sources.

scholarly journals Neural burst codes disguised as rate codes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ezekiel Williams ◽  
Alexandre Payeur ◽  
Albert Gidon ◽  
Richard Naud
Keyword(s):  
Information Transmission ◽  
Information Transfer ◽  
Cell Types ◽  
Neural Code ◽  
Spike Timing ◽  
Coding Strategies ◽  
Spike Patterns ◽  
Interval Distribution ◽  
Rule Out ◽  
Firing Statistics

AbstractThe burst coding hypothesis posits that the occurrence of sudden high-frequency patterns of action potentials constitutes a salient syllable of the neural code. Many neurons, however, do not produce clearly demarcated bursts, an observation invoked to rule out the pervasiveness of this coding scheme across brain areas and cell types. Here we ask how detrimental ambiguous spike patterns, those that are neither clearly bursts nor isolated spikes, are for neuronal information transfer. We addressed this question using information theory and computational simulations. By quantifying how information transmission depends on firing statistics, we found that the information transmitted is not strongly influenced by the presence of clearly demarcated modes in the interspike interval distribution, a feature often used to identify the presence of burst coding. Instead, we found that neurons having unimodal interval distributions were still able to ascribe different meanings to bursts and isolated spikes. In this regime, information transmission depends on dynamical properties of the synapses as well as the length and relative frequency of bursts. Furthermore, we found that common metrics used to quantify burstiness were unable to predict the degree with which bursts could be used to carry information. Our results provide guiding principles for the implementation of coding strategies based on spike-timing patterns, and show that even unimodal firing statistics can be consistent with a bivariate neural code.

scholarly journals Loss of Calretinin in L5a impairs the formation of the barrel cortex leading to abnormal whisker-mediated behaviors

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Mingzhao Su ◽  
Junhua Liu ◽  
Baocong Yu ◽  
Kaixing Zhou ◽  
Congli Sun ◽  
...  
Keyword(s):  
Information Integration ◽  
Pyramidal Neurons ◽  
Barrel Cortex ◽  
Sensory Information ◽  
Membrane Excitability ◽  
Novelty Preference ◽  
Layer 4 ◽  
Dendritic Complexity ◽  
Cortex System

AbstractThe rodent whisker-barrel cortex system has been established as an ideal model for studying sensory information integration. The barrel cortex consists of barrel and septa columns that receive information input from the lemniscal and paralemniscal pathways, respectively. Layer 5a is involved in both barrel and septa circuits and play a key role in information integration. However, the role of layer 5a in the development of the barrel cortex remains unclear. Previously, we found that calretinin is dynamically expressed in layer 5a. In this study, we analyzed calretinin KO mice and found that the dendritic complexity and length of layer 5a pyramidal neurons were significantly decreased after calretinin ablation. The membrane excitability and excitatory synaptic transmission of layer 5a neurons were increased. Consequently, the organization of the barrels was impaired. Moreover, layer 4 spiny stellate cells were not able to properly gather, leading to abnormal formation of barrel walls as the ratio of barrel/septum size obviously decreased. Calretinin KO mice exhibited deficits in exploratory and whisker-associated tactile behaviors as well as social novelty preference. Our study expands our knowledge of layer 5a pyramidal neurons in the formation of barrel walls and deepens the understanding of the development of the whisker-barrel cortex system.

Putative antihyperpyretic factor induced by LPS in spleen of guinea pigs

2005 ◽  
Vol 289 (3) ◽  
pp. R680-R687 ◽  
Author(s):  
Carlos Feleder ◽  
Vit Perlik ◽  
Ying Tang ◽  
Clark M. Blatteis
Keyword(s):  
Kupffer Cells ◽  
Guinea Pigs ◽  
Collateral Circulation ◽  
Splenic Vein ◽  
Inhibitory Factor ◽  
Febrile Response ◽  
Temperature Changes ◽  
The Core ◽  
Temporally Correlated

We reported previously that the onset of LPS-induced fever, irrespective of its route of administration, is temporally correlated with the appearance of LPS in the liver and that splenectomy significantly increases both the febrile response to LPS and the uptake of LPS by Kupffer cells (KC). To further evaluate the role of the spleen in LPS fever production, we ligated the splenic vein and, 7 and 30 days later, monitored the core temperature changes over 6 h after intraperitoneal (ip) injection of LPS (2 μg/kg). Both the febrile response and the uptake of LPS by KC were significantly augmented. Like splenectomy, splenic vein ligation (SVL) increased the febrile response and LPS uptake by KC until the collateral circulation developed, suggesting that the spleen may normally contribute an inhibitory factor that limits KC uptake of LPS and thus affects the febrile response. Subsequently, to verify the presence of this factor, we prepared splenic extracts from guinea pigs pretreated with LPS (8 μg/kg ip) or pyrogen-free saline, homogenized and ultrafiltered them, and injected them intravenously into splenectomized (Splex) guinea pigs pretreated with LPS (8 μg/kg ip). The results confirmed our presumption that the splenic extract from LPS-treated guinea pigs inhibits the exaggerated febrile response and the LPS uptake by the liver of Splex guinea pigs, indicating the presence of a putative splenic inhibitory factor, confirming the participation of the spleen in LPS-induced fever, and suggesting the existence of a novel antihyperpyretic mechanism. Preliminary data indicate that this factor is a lipid.

scholarly journals Circulating Secretin Activates Supraoptic Nucleus Oxytocin and Vasopressin Neurons via Noradrenergic Pathways in the Rat

Endocrinology ◽  
2010 ◽  
Vol 151 (6) ◽  
pp. 2681-2688 ◽  
Author(s):  
Sathya Velmurugan ◽  
Paula J. Brunton ◽  
Gareth Leng ◽  
John A. Russell
Keyword(s):  
Amino Acid ◽  
Firing Rate ◽  
Noradrenaline Release ◽  
Supraoptic Nucleus ◽  
Female Rats ◽  
Adrenoceptor Antagonist ◽  
Intracerebroventricular Infusion ◽  
Neuroendocrine Neurons ◽  
Vasopressin Neurons

Secretin is a 27-amino acid brain-gut peptide from duodenal S-cells. We tested the effects of systemic administration of secretin to simulate its postprandial release on neuroendocrine neurons of the supraoptic nucleus (SON) in urethane-anesthetized female rats. Secretin dose-dependently increased the firing rate of oxytocin neurons, more potently than cholecystokinin, and dose-dependently increased plasma oxytocin concentration. The effect of secretin on SON vasopressin neurons was also predominantly excitatory, in contrast to the inhibitory actions of cholecystokinin. To explore the involvement of noradrenergic inputs in secretin-induced excitation, benoxathian, an α1-adrenoceptor antagonist, was infused intracerebroventricularly. Benoxathian intracerebroventricular infusion blocked the excitation by secretin of both oxytocin and vasopressin neurons. To test the role of local noradrenaline release in the SON, benoxathian was microdialyzed onto the SON. The basal firing rate of oxytocin neurons was slightly reduced and the secretin-induced excitation was attenuated during benoxathian microdialysis. Hence, noradrenergic pathways mediate the excitation by systemic secretin of oxytocin neurons via α1-adrenoceptors in the SON. As both systemic secretin and oxytocin are involved in regulating gastrointestinal functions and natriuresis, systemically released secretin might act partly through oxytocin.

Cortical Representation of Auditory Space: Information-Bearing Features of Spike Patterns

2002 ◽  
Vol 87 (4) ◽  
pp. 1749-1762 ◽  
Author(s):  
Shigeto Furukawa ◽  
John C. Middlebrooks
Keyword(s):  
Sound Source ◽  
Neuronal Response ◽  
Source Location ◽  
Spike Timing ◽  
Spike Count ◽  
Cortical Representation ◽  
Auditory Space ◽  
Transmitted Information ◽  
Related Information ◽  
Spike Patterns

Previous studies have demonstrated that the spike patterns of cortical neurons vary systematically as a function of sound-source location such that the response of a single neuron can signal the location of a sound source throughout 360° of azimuth. The present study examined specific features of spike patterns that might transmit information related to sound-source location. Analysis was based on responses of well-isolated single units recorded from cortical area A2 in α-chloralose-anesthetized cats. Stimuli were 80-ms noise bursts presented from loudspeakers in the horizontal plane; source azimuths ranged through 360° in 20° steps. Spike patterns were averaged across samples of eight trials. A competitive artificial neural network (ANN) identified sound-source locations by recognizing spike patterns; the ANN was trained using the learning vector quantization learning rule. The information about stimulus location that was transmitted by spike patterns was computed from joint stimulus-response probability matrices. Spike patterns were manipulated in various ways to isolate particular features. Full-spike patterns, which contained all spike-count information and spike timing with 100-μs precision, transmitted the most stimulus-related information. Transmitted information was sensitive to disruption of spike timing on a scale of more than ∼4 ms and was reduced by an average of ∼35% when spike-timing information was obliterated entirely. In a condition in which all but the first spike in each pattern were eliminated, transmitted information decreased by an average of only ∼11%. In many cases, that condition showed essentially no loss of transmitted information. Three unidimensional features were extracted from spike patterns. Of those features, spike latency transmitted ∼60% more information than that transmitted either by spike count or by a measure of latency dispersion. Information transmission by spike patterns recorded on single trials was substantially reduced compared with the information transmitted by averages of eight trials. In a comparison of averaged and nonaveraged responses, however, the information transmitted by latencies was reduced by only ∼29%, whereas information transmitted by spike counts was reduced by 79%. Spike counts clearly are sensitive to sound-source location and could transmit information about sound-source locations. Nevertheless, the present results demonstrate that the timing of the first poststimulus spike carries a substantial amount, probably the majority, of the location-related information present in spike patterns. The results indicate that any complete model of the cortical representation of auditory space must incorporate the temporal characteristics of neuronal response patterns.

Sensory Transmission is Bi-directionally Modulated by Astrocytic Ca2+ in Barrel Cortex of Behaving Mice

2021 ◽  
Author(s):  
Simeng Gu ◽  
Wei Wang ◽  
Kuan Zhang ◽  
Rou Feng ◽  
Naling Li ◽  
...  
Keyword(s):  
Sensory Input ◽  
Barrel Cortex ◽  
Synaptic Function ◽  
Metabolic Clearance ◽  
Sleep State ◽  
Two Photon Microscopy ◽  
Two Photon ◽  
Sensory Transmission

Abstract Different effects of astrocyte during sleep and awake have been extensively studied, especially for metabolic clearance by the glymphatic system, which works during sleep and stops working during waking states. However, how astrocytes contribute to modulation of sensory transmission during sleep and awake animals remain largely unknown. Recent advances in genetically encoded Ca2+ indicators have provided a wealth of information on astrocytic Ca2+, especially in their fine perisynaptic processes, where astrocytic Ca2+ most likely affects the synaptic function. Here we use two-photon microscopy to image astrocytic Ca2+ signaling in freely moving mice trained to run on a wheel in combination with in vivo whole-cell recordings to evaluate the role of astrocytic Ca2+ signaling in different behavior states. We found that there are two kinds of astrocytic Ca2+ signaling: a small long-lasting Ca2+ increase during sleep state and a sharp widespread but short-long-lasting Ca2+ spike when the animal was awake (fluorescence increases were 23.2 ± 14.4% for whisker stimulation at sleep state, compared with 73.3 ± 11.7% for at awake state, paired t-test, p < 0.01). The small Ca2+ transients decreased extracellular K+, hyperpolarized the neurons, and suppressed sensory transmission; while the large Ca2+ wave enhanced sensory input, contributing to reliable sensory transmission in aroused states. Locus coeruleus activation works as a switch between these two kinds of astrocytic Ca2+ elevation. Thus, we show that cortical astrocytes play an important role in processing of sensory input. These two types of events appear to have different pharmacological sources and may play a different role in facilitating the efficacy of sensory transmission.

scholarly journals Loss of Calretinin in L5a Impairs the Formation of the Barrel Cortex Leading to Abnormal Behaviors

2021 ◽  
Author(s):  
Mingzhao Su ◽  
Junhua Liu ◽  
Baocong Yu ◽  
Kaixing Zhou ◽  
Congli Sun ◽  
...  
Keyword(s):  
Information Integration ◽  
Pyramidal Neurons ◽  
Barrel Cortex ◽  
Sensory Information ◽  
Membrane Excitability ◽  
Novelty Preference ◽  
Abnormal Behaviors ◽  
Dendritic Complexity ◽  
Cortex System

Abstract The rodent whisker-barrel cortex system has been established as an ideal model for studying sensory information integration. The barrel cortex consists of barrel and septa columns that receive information input from the lemniscal and paralemniscal pathways, respectively. L5a is involved in both barrel and septa circuits and play a key role in information integration. However, the role of L5a in the development of the barrel cortex remains unclear. Previously, we found that Calretinin is dynamically expressed in L5a. In this study, we analyzed Cr KO mice and found that the dendritic complexity and length of L5a pyramidal neurons were significantly decreased after Cr ablation. The membrane excitability and excitatory synaptic transmission of L5a neurons were increased. Consequently, the organization of the barrels was impaired. Moreover, L4 spiny stellate cells were not able to properly gather, leading to abnormal formation of barrel walls as the ratio of barrel/septum size obviously decreased. Cr KO mice exhibited deficits in exploratory and whisker-associated tactile behaviors as well as social novelty preference. Our study expands our knowledge of L5a pyramidal neurons in the formation of barrel walls and deepens the understanding of the development of the whisker-barrel cortex system.

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