scholarly journals Analysis of the Neuron Dynamics in Thalamic Reticular Nucleus by a Reduced Model

2021 ◽  
Vol 15 ◽  
Author(s):  
Chaoming Wang ◽  
Shangyang Li ◽  
Si Wu
Keyword(s):  
Bifurcation Analysis ◽  
Neuron Model ◽  
Salient Feature ◽  
Thalamic Reticular Nucleus ◽  
Reduced Model ◽  
Reticular Nucleus ◽  
Variable Model ◽  
Dynamical Mechanism

Strategically located between the thalamus and the cortex, the inhibitory thalamic reticular nucleus (TRN) is a hub to regulate selective attention during wakefulness and control the thalamic and cortical oscillations during sleep. A salient feature of TRN neurons contributing to these functions is their characteristic firing patterns, ranging in a continuum from tonic spiking to bursting spiking. However, the dynamical mechanism under these firing behaviors is not well understood. In this study, by applying a reduction method to a full conductance-based neuron model, we construct a reduced three-variable model to investigate the dynamics of TRN neurons. We show that the reduced model can effectively reproduce the spiking patterns of TRN neurons as observed in vivo and in vitro experiments, and meanwhile allow us to perform bifurcation analysis of the spiking dynamics. Specifically, we demonstrate that the rebound bursting of a TRN neuron is a type of “fold/homo-clinic” bifurcation, and the tonic spiking is the fold cycle bifurcation. Further one-parameter bifurcation analysis reveals that the transition between these discharge patterns can be controlled by the external current. We expect that this reduced neuron model will help us to further study the complicated dynamics and functions of the TRN network.

scholarly journals A thalamic reticular circuit for head direction cell tuning and spatial navigation

2019 ◽  
Author(s):  
Gil Vantomme ◽  
Zita Rovó ◽  
Romain Cardis ◽  
Elidie Béard ◽  
Georgia Katsioudi ◽  
...  
Keyword(s):  
Spatial Navigation ◽  
Sensory Information ◽  
Search Strategies ◽  
Retrosplenial Cortex ◽  
Thalamic Reticular Nucleus ◽  
Reticular Nucleus ◽  
Head Direction ◽  
Thalamic Nuclei

SummaryTo navigate in space, an animal must refer to sensory cues to orient and move. Circuit and synaptic mechanisms that integrate cues with internal head-direction (HD) signals remain, however, unclear. We identify an excitatory synaptic projection from the presubiculum (PreS) and the multisensory-associative retrosplenial cortex (RSC) to the anterodorsal thalamic reticular nucleus (TRN), so far classically implied in gating sensory information flow. In vitro, projections to TRN involved AMPA/NMDA-type glutamate receptors that initiated TRN cell burst discharge and feedforward inhibition of anterior thalamic nuclei. In vivo, chemogenetic anterodorsal TRN inhibition modulated PreS/RSC-induced anterior thalamic firing dynamics, broadened the tuning of thalamic HD cells, and led to preferential use of allo-over egocentric search strategies in the Morris water maze. TRN-dependent thalamic inhibition is thus an integral part of limbic navigational circuits wherein it coordinates external sensory and internal HD signals to regulate the choice of search strategies during spatial navigation.

scholarly journals Corticothalamic gating of population auditory thalamocortical transmission in mouse

2019 ◽  
Author(s):  
Baher A. Ibrahim ◽  
Caitlin Murphy ◽  
Guido Muscioni ◽  
Aynaz Taheri ◽  
Georgiy Yudintsev ◽  
...  
Keyword(s):  
Receptive Field ◽  
Auditory Cortex ◽  
Cortical Neurons ◽  
Feedback Inhibition ◽  
Thalamic Reticular Nucleus ◽  
Reticular Nucleus ◽  
Linear Filter ◽  
Sensory Stimuli

AbstractSince the discovery of the receptive field, scientists have tracked receptive field structure to gain insights about mechanisms of sensory processing. At the level of the thalamus and cortex, this linear filter approach has been challenged by findings that populations of cortical neurons respond in a stereotyped fashion to sensory stimuli. Here, we elucidate a possible mechanism by which gating of cortical representations occurs. All-or-none population responses (here called “ON” and “OFF” responses) were observed in vivo and in vitro in the mouse auditory cortex at near-threshold acoustic or electrical stimulation. ON-responses were associated with previously-described UP states in the auditory cortex. OFF-responses in the cortex were only eliminated by blocking GABAergic inhibition in the thalamus. Opto- and chemogenetic silencing of NTSR-positive corticothalamic layer 6 (CTL6) neurons as well as the pharmacological blocking of the thalamic reticular nucleus (TRN) retrieved the missing cortical responses, suggesting that the corticothalamic feedback inhibition via TRN controls the gating of thalamocortical activity. Moreover, the oscillation of the pre-stimulus activity of corticothalamic cells predicted the cortical ON vs. OFF responses, suggesting that underlying cortical oscillation controls thalamocortical gating. These data suggest that the thalamus may recruit cortical ensembles rather than linearly encoding ascending stimuli and that corticothalamic projections play a key role in selecting cortical ensembles for activation.

Oscillatory synaptic interactions between ventroposterior and reticular neurons in mouse thalamus in vitro

1994 ◽  
Vol 72 (4) ◽  
pp. 1993-2003 ◽  
Author(s):  
R. A. Warren ◽  
A. Agmon ◽  
E. G. Jones
Keyword(s):  
Receptor Antagonist ◽  
Gabab Receptor ◽  
Initial Response ◽  
Thalamic Reticular Nucleus ◽  
Reticular Nucleus ◽  
Excitatory Postsynaptic Potential ◽  
Postsynaptic Potential ◽  
Synaptic Interactions ◽  
Gabaa Receptor Antagonist

1. The thalamic reticular nucleus (RTN) has reciprocal connections with relay neurons in the dorsal thalamus. We used whole cell recording in a mouse in vitro slice preparation maintained at room temperature to study the synaptic interactions between the RTN and the ventroposterior thalamic nucleus (VP) during evoked low-frequency oscillations. 2. After a single electrical stimulus of the internal capsule, postsynaptic potentials (PSPs) were recorded in all VP and RTN neurons. In 76% of slices, there was an initial response followed by recurrent PSPs lasting for up to 8 s and with a frequency of approximately 2 Hz in both the VP and RTN. 3. In RTN neurons the initial response consisted of a fast excitatory postsynaptic potential (EPSP) that generated a burst of action potentials. Recurrent PSPs consisted of barrages of EPSPs that often reached burst threshold. The structure of subthreshold EPSP barrages in RTN neurons suggested that they were generated by bursting VP neurons. 4. In VP neurons the stimulus usually evoked a small EPSP followed by a large inhibitory postsynaptic potential (IPSP) that was often followed by a rebound burst. This initial response was often followed by a series of recurrent IPSPs presumably generated by RTN bursts, because intrinsic inhibitory neurons are absent in rodent VP. 5. IPSPs in VP neurons and recurrent EPSPs in RTN neurons were completely abolished by application of a gamma-aminobutyric acid-A (GABAA) receptor antagonist. A GABAB receptor antagonist produced no or little change in either the initial or recurrent response. 6. Recurrent IPSPs in VP neurons were abolished by glutamate receptor antagonists before the initial IPSP, which always remained stimulus dependent. 7. The dependency of recurring IPSPs in VP and recurring EPSPs in RTN upon GABA-mediated inhibition and excitatory amino acid-mediated excitation, plus the character of recurring EPSPs in the RTN strongly suggest that the recurring events were generated through reverse-reciprocal synaptic interactions between VP and RTN neurons. These synaptic interactions most likely play an important role in thalamic oscillations in behavior.

scholarly journals 0028 GABAA Receptors Of The Thalamic Reticular Nucleus Regulate Sleep Spindles: An In Vivo Investigation By CRISPR-cas9 Genetic Abscission

SLEEP ◽  
2018 ◽  
Vol 41 (suppl_1) ◽  
pp. A12-A12
Author(s):  
D S Uygun ◽  
C Yang ◽  
H Miwa ◽  
J T McKenna ◽  
J M McNally ◽  
...  
Keyword(s):  
Gabaa Receptors ◽  
Thalamic Reticular Nucleus ◽  
Reticular Nucleus ◽  
Sleep Spindles

scholarly journals Corticothalamic Inhibition in the Thalamic Reticular Nucleus

2004 ◽  
Vol 91 (2) ◽  
pp. 759-766 ◽  
Author(s):  
Liming Zhang ◽  
Edward G. Jones
Keyword(s):  
Barrel Cortex ◽  
Thalamic Reticular Nucleus ◽  
Reticular Nucleus ◽  
Receptor Antagonists ◽  
Experimental Conditions ◽  
Inhibitory Network ◽  
Corticothalamic Projection ◽  
Substantial Network ◽  
Layer Vi

Mutual inhibition between the GABAergic cells of the thalamic reticular nucleus (RTN) is important in regulating oscillations in the thalamocortical network, promoting those in the spindle range of frequencies over those at lower frequencies. Excitatory inputs to the RTN from the cerebral cortex are numerically large and particularly powerful in inducing spindles. However, the extent to which corticothalamic influences can engage the inhibitory network of the RTN has not been fully explored. Focal electrical stimulation of layer VI in the barrel cortex of the mouse thalamocortical slice in vitro resulted in prominent di- or polysynaptic inhibitory postsynaptic currents (IPSCs) in RTN cells under the experimental conditions used. The majority of cortically induced responses consisted of mixed PSCs in which the inhibitory component predominated or of large IPSCs alone, implying inhibition of neighboring cells by other, cortically excited RTN cells. Within the mixed PSCs, fixed and variable latency components could commonly be identified. IPSCs could be blocked by application of ionotropic glutamate receptor antagonists or of GABAA receptor antagonists, also indicating their dependence on corticothalamic excitation triggering disynaptic or polysynaptic inhibition. Spontaneous GABAA receptor-dependent IPSCs were routinely observed in the RTN and, taken together with the results of cortical stimulation, indicate the existence of a substantial network of intrareticular inhibitory connections that can be effectively recruited by the corticothalamic system. These results suggest activation of cortical excitatory inputs triggers the propagation of inhibitory currents within the RTN and support the view that activation of the RTN from the somatosensory cortex, although focused by the topography of the corticothalamic projection, is capable of disynaptically engaging the whole inhibitory network of the RTN, by local and probably by reentrant GABAA receptor–based synapses, thus spreading the corticothalamic influence throughout the RTN.

scholarly journals Spindle-Like Thalamocortical Synchronization in a Rat Brain Slice Preparation

2000 ◽  
Vol 84 (2) ◽  
pp. 1093-1097 ◽  
Author(s):  
Virginia Tancredi ◽  
Giuseppe Biagini ◽  
Margherita D'Antuono ◽  
Jacques Louvel ◽  
René Pumain ◽  
...  
Keyword(s):  
Rat Brain ◽  
Kynurenic Acid ◽  
Brain Slice ◽  
Excitatory Amino Acid ◽  
Brain Slices ◽  
Reticular Nucleus ◽  
Antidromic Responses ◽  
Rat Brain Slice

We obtained rat brain slices (550–650 μm) that contained part of the frontoparietal cortex along with a portion of the thalamic ventrobasal complex (VB) and of the reticular nucleus (RTN). Maintained reciprocal thalamocortical connectivity was demonstrated by VB stimulation, which elicited orthodromic and antidromic responses in the cortex, along with re-entry of thalamocortical firing originating in VB neurons excited by cortical output activity. In addition, orthodromic responses were recorded in VB and RTN following stimuli delivered in the cortex. Spontaneous and stimulus-induced coherent rhythmic oscillations (duration = 0.4–3.5 s; frequency = 9–16 Hz) occurred in cortex, VB, and RTN during application of medium containing low concentrations of the K+ channel blocker 4-aminopyridine (0.5–1 μM). This activity, which resembled electroencephalograph (EEG) spindles recorded in vivo, disappeared in both cortex and thalamus during application of the excitatory amino acid receptor antagonist kynurenic acid in VB ( n = 6). By contrast, cortical application of kynurenic acid ( n = 4) abolished spindle-like oscillations at this site, but not those recorded in VB, where their frequency was higher than under control conditions. Our findings demonstrate the preservation of reciprocally interconnected cortical and thalamic neuron networks that generate thalamocortical spindle-like oscillations in an in vitro rat brain slice. As shown in intact animals, these oscillations originate in the thalamus where they are presumably caused by interactions between RTN and VB neurons. We propose that this preparation may help to analyze thalamocortical synchronization and to understand the physiopathogenesis of absence attacks.

Sulfated cholecystokinin octapeptide in the rat: pontomedullary distribution and modulation of the respiratory pattern

1999 ◽  
Vol 77 (7) ◽  
pp. 490-504 ◽  
Author(s):  
Howard H Ellenberger ◽  
Frank M Smith
Keyword(s):  
Respiratory Rhythm ◽  
Mean Amplitude ◽  
Neonatal Rat ◽  
Respiratory Pattern ◽  
Reticular Nucleus ◽  
Adult Rats ◽  
Cholecystokinin Octapeptide ◽  
Ventral Respiratory Group

We performed anatomical and physiological studies to determine the site and actions of sulfated cholecystokinin octapeptide (CCK8-S) on breathing. Peptide locations were determined by combined immunodetection of CCK8-S- containing synaptic varicosities and retrograde labeling of medullary neurons projecting to the ventral respiratory group. Retrogradely labeled neurons and CCK8-S immunolabeled varicosities overlapped within the nuclei of the solitary tract, ventral respiratory group, and the Kölliker-Fuse nucleus. Additional CCK8-S immunoreactive terminals were located in the rostroventrolateral medullary reticular nucleus, lateral paragigantocellular reticular nucleus, and the caudal pontine reticular nucleus. The respiratory effects of CCK8-S, which binds to CCKA and CCKB receptors, were examined by intravenous injection in adult rats and by bath application in the in vitro neonatal rat brainstem - spinal cord preparation. CCK8-S produced an increase in the mean amplitude of diaphragmatic electromyogram (EMG) of 28 ± 35% (SD) and a decrease in mean respiratory interval of 13 ± 4% in vivo. In vitro, CCK8-S significantly increased inspiratory duration and decreased respiratory interval, primarily by shortening expiratory duration. CCK8-unsulfated, a specific agonist for CCKB receptors, did not produce these effects. CCK8-S effects in the in vitro preparation were partially blocked by the CCK receptor antagonist lorglumide (final bath concentration 600 nM). These results suggest that CCK8-S modulates the respiratory rhythm via CCKA receptors within one or more medullary or pontine respiratory groups in both neonatal and adult rats.Key words: neuropeptide, ventral respiratory group, medulla, pons, respiratory network.

Inhibitory Interactions Between Ferret Thalamic Reticular Neurons

2002 ◽  
Vol 87 (5) ◽  
pp. 2571-2576 ◽  
Author(s):  
Yousheng Shu ◽  
David A. McCormick
Keyword(s):  
Reversal Potential ◽  
Thalamic Reticular Nucleus ◽  
Reticular Nucleus ◽  
Inhibitory Input ◽  
Inhibitory Interaction ◽  
Postsynaptic Potentials ◽  
Inhibitory Postsynaptic Potentials ◽  
Reticular Neurons ◽  
Inhibitory Interactions

The thalamic reticular nucleus (nRt) provides an important inhibitory input to thalamic relay nuclei and is central in the generation of both normal and abnormal thalamocortical activities. Although local inhibitory interactions between these neurons may play an important role in controlling thalamocortical activities, the physiological features of this interaction have not been fully investigated. Here we sought to establish the nature of inhibitory interaction between nRt neurons with intracellular and extracellular recordings in slices of ferret nRt maintained in vitro. In many nRt neurons, intracellular recordings revealed spontaneous inhibitory postsynaptic potentials (IPSPs). In addition, the local excitation of nRt cells with glutamate led to the generation of IPSPs in the intracellularly recorded nRt neuron. These evoked IPSPs exhibited an average reversal potential of −72 mV and could be blocked by picrotoxin, a GABAA-receptor antagonist. These results indicate that nRt neurons interact locally through the activation of GABAA receptor-mediated inhibitory postsynaptic potentials. This lateral inhibition may play an important role in controlling the responsiveness of these cells to cortical and thalamic excitatory inputs in both normal and abnormal thalamocortical function.

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