Behaviorally Relevant Burst Coding in Primary Sensory Neurons

2009 ◽  
Vol 102 (2) ◽  
pp. 1086-1091 ◽  
Author(s):  
Patrick Sabourin ◽  
Gerald S. Pollack
Keyword(s):  
Sensory Neurons ◽  
Sensory Processing ◽  
Action Potentials ◽  
Temporal Structure ◽  
Primary Sensory Neurons ◽  
Acoustic Stimuli ◽  
Feature Detectors ◽  
Salient Stimulus ◽  
Stimulus Features ◽  
Temporally Correlated

Bursts of action potentials in sensory interneurons are believed to signal the occurrence of particularly salient stimulus features. Previous work showed that bursts in an identified, ultrasound-tuned interneuron (AN2) of the cricket Teleogryllus oceanicus code for conspicuous increases in amplitude of an ultrasound stimulus, resulting in behavioral responses that are interpreted as avoidance of echolocating bats. We show that the primary sensory neurons that inform AN2 about high-frequency acoustic stimuli also produce bursts. As is the case for AN2, bursts in sensory neurons perform better as feature detectors than isolated, nonburst, spikes. Bursting is temporally correlated between sensory neurons, suggesting that on occurrence of a salient stimulus feature, AN2 will receive strong synaptic input in the form of coincident bursts, from several sensory neurons, and that this might result in bursting in AN2. Our results show that an important feature of the temporal structure of interneuron spike trains can be established at the earliest possible level of sensory processing, i.e., that of the primary sensory neuron.

A-Type Voltage-Gated K+ Currents Influence Firing Properties of Isolectin B4-Positive But Not Isolectin B4-Negative Primary Sensory Neurons

2005 ◽  
Vol 93 (6) ◽  
pp. 3401-3409 ◽  
Author(s):  
Amaresh Vydyanathan ◽  
Zi-Zhen Wu ◽  
Shao-Rui Chen ◽  
Hui-Lin Pan
Keyword(s):  
Sensory Neurons ◽  
Action Potentials ◽  
Neuronal Excitability ◽  
Cell Voltage ◽  
Primary Sensory Neurons ◽  
Drg Neurons ◽  
Voltage Gated ◽  
The Difference ◽  
Firing Properties ◽  
Isolectin B4

Voltage-gated K+ channels (Kv) in primary sensory neurons are important for regulation of neuronal excitability. The dorsal root ganglion (DRG) neurons are heterogeneous, and the types of native Kv currents in different groups of nociceptive DRG neurons are not fully known. In this study, we determined the difference in the A-type Kv current and its influence on the firing properties between isolectin B4 (IB4)-positive and -negative DRG neurons. Whole cell voltage- and current-clamp recordings were performed on acutely dissociated small DRG neurons of rats. The total Kv current density was significantly higher in IB4-positive than that in IB4-negative neurons. Also, 4-aminopyridine (4-AP) produced a significantly greater reduction in Kv currents in IB4-positive than in IB4-negative neurons. In contrast, IB4-negative neurons exhibited a larger proportion of tetraethylammonium-sensitive Kv currents. Furthermore, IB4-positive neurons showed a longer latency of firing and required a significantly larger amount of current injection to evoke action potentials. 4-AP significantly decreased the latency of firing and increased the firing frequency in IB4-positive but not in IB4-negative neurons. Additionally, IB4-positive neurons are immunoreactive to Kv1.4 but not to Kv1.1 and Kv1.2 subunits. Collectively, this study provides new information that 4-AP–sensitive A-type Kv currents are mainly present in IB4-positive DRG neurons and preferentially dampen the initiation of action potentials of this subpopulation of nociceptors. The difference in the density of A-type Kv currents contributes to the distinct electrophysiological properties of IB4-positive and -negative DRG neurons.

scholarly journals Neuronal Transmission of Subthreshold Periodic Stimuli Via Symbolic Spike Patterns

Entropy ◽  
2020 ◽  
Vol 22 (5) ◽  
pp. 524
Author(s):  
Maria Masoliver ◽  
Cristina Masoller
Keyword(s):  
Spike Train ◽  
Sensory Neurons ◽  
Action Potentials ◽  
Temporal Structure ◽  
Spike Trains ◽  
Periodic Signal ◽  
Stimulus Information ◽  
Neural Noise ◽  
Neuronal Transmission ◽  
Spike Patterns

We study how sensory neurons detect and transmit a weak external stimulus. We use the FitzHugh–Nagumo model to simulate the neuronal activity. We consider a sub-threshold stimulus, i.e., the stimulus is below the threshold needed for triggering action potentials (spikes). However, in the presence of noise the neuron that perceives the stimulus fires a sequence of action potentials (a spike train) that carries the stimulus’ information. To yield light on how the stimulus’ information can be encoded and transmitted, we consider the simplest case of two coupled neurons, such that one neuron (referred to as neuron 1) perceives a subthreshold periodic signal but the second neuron (neuron 2) does not perceive the signal. We show that, for appropriate coupling and noise strengths, both neurons fire spike trains that have symbolic patterns (defined by the temporal structure of the inter-spike intervals), whose frequencies of occurrence depend on the signal’s amplitude and period, and are similar for both neurons. In this way, the signal information encoded in the spike train of neuron 1 propagates to the spike train of neuron 2. Our results suggest that sensory neurons can exploit the presence of neural noise to fire spike trains where the information of a subthreshold stimulus is encoded in over expressed and/or in less expressed symbolic patterns.

scholarly journals Continuous, multidimensional coding of 3D complex tactile stimuli by primary sensory neurons of the vibrissal system

2021 ◽  
Vol 118 (32) ◽  
pp. e2020194118
Author(s):  
Nicholas E. Bush ◽  
Sara A. Solla ◽  
Mitra J. Z. Hartmann
Keyword(s):  
Sensory Neurons ◽  
Three Dimensional ◽  
Primary Sensory Neurons ◽  
Tactile Information ◽  
Central Neurons ◽  
Information Bottleneck ◽  
Tactile Stimuli ◽  
Functional Classes ◽  
Stimulus Features ◽  
Multidimensional Representation

Across all sensory modalities, first-stage sensory neurons are an information bottleneck: they must convey all information available for an animal to perceive and act in its environment. Our understanding of coding properties of primary sensory neurons in the auditory and visual systems has been aided by the use of increasingly complex, naturalistic stimulus sets. By comparison, encoding properties of primary somatosensory afferents are poorly understood. Here, we use the rodent whisker system to examine how tactile information is represented in primary sensory neurons of the trigeminal ganglion (Vg). Vg neurons have long been thought to segregate into functional classes associated with separate streams of information processing. However, this view is based on Vg responses to restricted stimulus sets which potentially underreport the coding capabilities of these neurons. In contrast, the current study records Vg responses to complex three-dimensional (3D) stimulation while quantifying the complete 3D whisker shape and mechanics, thereby beginning to reveal their full representational capabilities. The results show that individual Vg neurons simultaneously represent multiple mechanical features of a stimulus, do not preferentially encode principal components of the stimuli, and represent continuous and tiled variations of all available mechanical information. These results directly contrast with proposed codes in which subpopulations of Vg neurons encode select stimulus features. Instead, individual Vg neurons likely overcome the information bottleneck by encoding large regions of a complex sensory space. This proposed tiled and multidimensional representation at the Vg directly constrains the computations performed by more central neurons of the vibrissotrigeminal pathway.

scholarly journals Electrophysiological Identification of Tonic and Phasic Neurons in Sensory Dorsal Root Ganglion and Their Distinct Implications in Inflammatory Pain

2014 ◽  
pp. 793-799 ◽  
Author(s):  
Y.-Q. YU ◽  
X.-F. CHEN ◽  
Y. YANG ◽  
F. YANG ◽  
J. CHEN
Keyword(s):  
Sensory Neurons ◽  
Inflammatory Pain ◽  
Action Potentials ◽  
Dorsal Root ◽  
Dependent Manner ◽  
Primary Sensory Neurons ◽  
Drg Neurons ◽  
Fluorescent Tracer ◽  
Firing Patterns ◽  
Venom Toxin

In the mammalian autonomic nervous system, tonic and phasic neurons can be differentiated on firing patterns in response to long depolarizing current pulse. However, the similar firing patterns in the somatic primary sensory neurons and their functional significance are not well investigated. Here, we identified two types of neurons innervating somatic sensory in rat dorsal root ganglia (DRG). Tonic neurons fire action potentials (APs) in an intensity-dependent manner, whereas phasic neurons typically generate only one AP firing at the onset of stimulation regardless of intensity. Combining retrograde labeling of somatic DRG neurons with fluorescent tracer DiI, we further find that these neurons demonstrate distinct changes under inflammatory pain states induced by complete Freund’s adjuvant (CFA) or bee venom toxin melittin. In tonic neurons, CFA and melittin treatments significantly decrease rheobase and AP durations (depolarization and repolarization), enhance amplitudes of overshoot and afterhyperpolarization (AHP), and increase the number of evoked action potentials. In phasic neurons, however, the same inflammation treatments cause fewer changes in these electrophysiological parameters except for the increased overshoot and decreased AP durations. In the present study, we find that tonic neurons are more hyperexcitable than phasic neurons after peripheral noxious inflammatory stimulation. The results indicate the distinct contributions of two types of DRG neurons in inflammatory pain.

scholarly journals Analyzing the Carotenoid Composition of Melilot (Melilotus officinalis (L.) Pall.) Extracts and the Effects of Isolated (All-E)-lutein-5,6-epoxide on Primary Sensory Neurons and Macrophages

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 503
Author(s):  
Györgyi Horváth ◽  
Eszter Csikós ◽  
Eichertné Violetta Andres ◽  
Tímea Bencsik ◽  
Anikó Takátsy ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Sensory Neurons ◽  
Biological Activities ◽  
Water Soluble ◽  
Soluble Form ◽  
Primary Sensory Neurons ◽  
Isolation And Identification ◽  
Melilotus Officinalis ◽  
Carotenoid Composition ◽  
Anti Inflammatory

Melilotus officinalis is known to contain several types of secondary metabolites. In contrast, the carotenoid composition of this medicinal plant has not been investigated, although it may also contribute to the biological activities of the drug, such as anti-inflammatory effects. Therefore, this study focuses on the isolation and identification of carotenoids from Meliloti herba and on the effect of isolated (all-E)-lutein 5,6-epoxide on primary sensory neurons and macrophages involved in nociception, as well as neurogenic and non-neurogenic inflammatory processes. The composition of the plant extracts was analyzed by high performance liquid chromatography (HPLC). The main carotenoid was isolated by column liquid chromatography (CLC) and identified by MS and NMR. The effect of water-soluble lutein 5,6-epoxide-RAMEB (randomly methylated-β-cyclodextrin) was investigated on Ca2+-influx in rat primary sensory neurons induced by the activation of the transient receptor potential ankyrin 1 receptor agonist to mustard-oil and on endotoxin-induced IL-1β release from isolated mouse peritoneal macrophages. (all-E)-Lutein 5,6-epoxide significantly decreased the percent of responsive primary sensory neurons compared to the vehicle-treated stimulated control. Furthermore, endotoxin-evoked IL-1β release from macrophages was significantly decreased by 100 µM lutein 5,6-epoxide compared to the vehicle-treated control. The water-soluble form of lutein 5,6-epoxide-RAMEB decreases the activation of primary sensory neurons and macrophages, which opens perspectives for its analgesic and anti-inflammatory applications.

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