Thalamic reticular nucleus in Caiman crocodilus: Relationship with the dorsal thalamus

Neuroscience ◽  
2016 ◽  
Vol 322 ◽  
pp. 430-451 ◽  
Author(s):  
M.B. Pritz
Keyword(s):  
Thalamic Reticular Nucleus ◽  
Reticular Nucleus ◽  
Dorsal Thalamus ◽  
Caiman Crocodilus

Thalamic Reticular Nucleus in Caiman crocodilus: Immunohistochemical Staining

2018 ◽  
Vol 92 (3-4) ◽  
pp. 142-166 ◽  
Author(s):  
Michael B. Pritz
Keyword(s):  
Glutamic Acid ◽  
Glutamic Acid Decarboxylase ◽  
Immunohistochemical Staining ◽  
Medial Forebrain Bundle ◽  
Transverse Plane ◽  
Thalamic Reticular Nucleus ◽  
Reticular Nucleus ◽  
Acid Decarboxylase ◽  
Caiman Crocodilus ◽  
Monoclonal Mouse

The thalamic reticular nucleus in reptiles, Caiman crocodilus, shares a number of morphological similarities with its counterpart in mammals. In view of the immunohistochemical properties of this nucleus in mammals and the more recently identified complexity of this neuronal aggregate in Caiman, this nucleus was investigated using a number of antibodies. These results were compared with findings described for other amniotes. The following antibodies gave consistent and reproducible results: polyclonal sheep anti-parvalbumin (PV), monoclonal mouse anti-PV, and polyclonal sheep anti-glutamic acid decarboxylase (GAD). In the transverse plane, this nucleus is divided into two. In each part, a compact group of cells sits on top of the fibers of the forebrain bundle with scattered cells among these fibers. In the lateral forebrain bundle, this neuronal aggregate is represented by the dorsal peduncular nucleus and the perireticular nucleus while, in the medial forebrain bundle, these parts are the interstitial nucleus and the scattered cells in this fiber tract. The results of this study are the following. First, the thalamic reticular nucleus of Caiman contains GAD(+) and PV(+) neurons, which is similar to what has been described in other amniotes. Second, the morphology and distribution of many GAD(+) and PV(+) neurons in the dorsal peduncular and perireticular nuclei are similar and suggest that these neurons colocalize these markers. Third, neurons in the interstitial nucleus and in the medial forebrain bundle are GAD(+) and PV(+). At the caudal pole of the thalamic reticular nucleus, PV immunoreactive cells predominated and avoided the central portion of this nucleus where GAD(+) cells were preferentially located. However, GAD(+) cells were sparse when compared with PV(+) cells. This immunohistochemically different area in the caudal pole is considered to be an area separate from the thalamic reticular nucleus.

scholarly journals Propagation of cortical activity via open-loop intrathalamic architectures: a computational analysis

2019 ◽  
Author(s):  
Jeffrey W. Brown ◽  
Aynaz Taheri ◽  
Robert V. Kenyon ◽  
Tanya Berger-Wolf ◽  
Daniel A. Llano
Keyword(s):  
Closed Loop ◽  
Neural Model ◽  
Signal Propagation ◽  
Open Loop ◽  
Thalamic Reticular Nucleus ◽  
Oscillatory Activity ◽  
Reticular Nucleus ◽  
Dorsal Thalamus ◽  
In Series ◽  
Intracortical Connectivity

AbstractPropagation of signals across the cerebral cortex is a core component of many cognitive processes and is generally thought to be mediated by direct intracortical connectivity. The thalamus, by contrast, is considered to be devoid of internal connections and organized as a collection of parallel inputs to the cortex. Here, we provide evidence that “open-loop” intrathalamic connections involving the thalamic reticular nucleus (TRN) can support propagation of oscillatory activity across the cortex. Recent studies support the existence of open-loop thalamo-reticulo-thalamic (TC-TRN-TC) synaptic motifs in addition to traditional closed-loop architectures. We hypothesized that open-loop structural modules, when connected in series, might underlie thalamic and, therefore cortical, signal propagation. Using a supercomputing platform to simulate thousands of permutations of a thalamo-reticular-cortical network and allowing select synapses to vary both by class and individually, we evaluated the relative capacities of closed- and open-loop TC-TRN-TC synaptic configurations to support both propagation and oscillation. We observed that 1) signal propagation was best supported in networks possessing strong open-loop TC-TRN-TC connectivity; 2) intrareticular synapses were neither primary substrates of propagation nor oscillation; and 3) heterogeneous synaptic networks supported more robust propagation of oscillation than their homogeneous counterparts. These findings suggest that open-loop heterogeneous intrathalamic architectures complement direct intracortical connectivity to facilitate cortical signal propagation.Significance StatementInteractions between the dorsal thalamus and thalamic reticular nucleus (TRN) are speculated to contribute to phenomena such as arousal, attention, sleep, and seizures. Despite the importance of the TRN, the synaptic microarchitectures forming the basis for dorsal thalamus-TRN interactions are not fully understood. The computational neural model we present incorporates “open-loop” thalamo-reticular-thalamic (TC-TRN-TC) synaptic motifs, which have been experimentally observed. We elucidate how open-loop motifs possess the capacity to shape the propagative properties of signals intrinsic to the thalamus and evaluate the wave dynamics they support relative to closed-loop TC-TRN-TC pathways and intrareticular synaptic connections. Our model also generates predictions regarding how different spatial distributions of reticulothalamic and intrareticular synapses affect these signaling properties.

scholarly journals Open-loop organization of thalamic reticular nucleus and dorsal thalamus: a computational model

2015 ◽  
Vol 114 (4) ◽  
pp. 2353-2367 ◽  
Author(s):  
Adam M. Willis ◽  
Bernard J. Slater ◽  
Ekaterina D. Gribkova ◽  
Daniel A. Llano
Keyword(s):  
Closed Loop ◽  
Open Loop ◽  
Tunable Filter ◽  
Cortical Activation ◽  
Thalamic Reticular Nucleus ◽  
Reticular Nucleus ◽  
Loop Model ◽  
Dependent Manner ◽  
Dorsal Thalamus ◽  
Low Threshold

The thalamic reticular nucleus (TRN) is a shell of GABAergic neurons that surrounds the dorsal thalamus. Previous work has shown that TRN neurons send GABAergic projections to thalamocortical (TC) cells to form reciprocal, closed-loop circuits. This has led to the hypothesis that the TRN is responsible for oscillatory phenomena, such as sleep spindles and absence seizures. However, there is emerging evidence that open-loop circuits are also found between TRN and TC cells. The implications of open-loop configurations are not yet known, particularly when they include time-dependent nonlinearities in TC cells such as low-threshold bursting. We hypothesized that low-threshold bursting in an open-loop circuit could be a mechanism by which the TRN could paradoxically enhance TC activation, and that enhancement would depend on the relative timing of TRN vs. TC cell stimulation. To test this, we modeled small circuits containing TC neurons, TRN neurons, and layer 4 thalamorecipient cells in both open- and closed-loop configurations. We found that open-loop TRN stimulation, rather than universally depressing TC activation, increased cortical output across a broad parameter space, modified the filter properties of TC neurons, and altered the mutual information between input and output in a frequency-dependent and T-type calcium channel-dependent manner. Therefore, an open-loop model of TRN-TC interactions, rather than suppressing transmission through the thalamus, creates a tunable filter whose properties may be modified by outside influences onto the TRN. These simulations make experimentally testable predictions about the potential role for the TRN for flexible enhancement of cortical activation.

scholarly journals Spindle oscillations are generated in the dorsal thalamus and modulated by the thalamic reticular nucleus

2008 ◽  
Author(s):  
Chun-Hua Liu ◽  
Yi Ping Guo ◽  
Xian-Kai Meng ◽  
Yan-Qin Yu ◽  
Ying Xiong ◽  
...  
Keyword(s):  
Thalamic Reticular Nucleus ◽  
Reticular Nucleus ◽  
Dorsal Thalamus

scholarly journals Functional topographic organization of the motor reticulothalamic pathway

2015 ◽  
Vol 113 (9) ◽  
pp. 3090-3097 ◽  
Author(s):  
Ying-Wan Lam ◽  
S. Murray Sherman
Keyword(s):  
Laser Scanning ◽  
Thalamic Reticular Nucleus ◽  
Reticular Nucleus ◽  
Thalamic Nuclei ◽  
Dorsal Thalamus ◽  
Thalamic Relay ◽  
Thalamocortical Projections ◽  
Motor Information ◽  
Laser Scanning Photostimulation ◽  
Similar Organization

The thalamic reticular nucleus (TRN) is a thin layer of GABAergic cells lying rostral and lateral to the dorsal thalamus, and its projection to thalamic relay cells (i.e., the reticulothalamic pathway) strongly inhibits these cells. In an attempt to extend earlier studies of reticulothalamic connections to sensory thalamic nuclei, we used laser-scanning photostimulation to study the reticulothalamic projections to the main motor thalamic relays, the ventral anterior and lateral (VA and VL) nuclei, as well as to the nearby central lateral (CL) thalamic nucleus. VA/VL and the earlier studied somatosensory thalamic nuclei are considered “core” nuclei with topographic thalamocortical projections, whereas CL is thought to be a “matrix” nucleus with diffuse thalamocortical projections. We found that the TRN input footprints to VA/VL and CL are spatially localized and topographic and generally conform to the patterns established earlier for the TRN projections to sensory thalamic relays. These remarkable similarities suggest similar organization of reticulothalamic pathways and TRN regulation of thalamocortical communication for motor and sensory systems and perhaps also for core and matrix thalamus. Furthermore, we found that VA/VL and CL shared overlapping TRN input regions, suggesting that CL may also be involved in the relay of motor information.

scholarly journals Deficient thalamo-cortical networks dynamics and sleep homeostatic processes in a redox dysregulation model relevant to schizophrenia.

2021 ◽  
Author(s):  
Christina Czekus ◽  
Pascal Steullet ◽  
Thomas Rusterholz ◽  
Ivan Bozic ◽  
Kim Do Cuenod ◽  
...  
Keyword(s):  
Recovery Period ◽  
Nrem Sleep ◽  
Sleep Architecture ◽  
Anterior Cingulate ◽  
Thalamic Reticular Nucleus ◽  
Reticular Nucleus ◽  
Glutathione Synthetase ◽  
Cortical Networks ◽  
Dorsal Thalamus ◽  
Sleep Homeostasis

A growing body of evidence implicates thalamo-cortical oscillations with the neuropathophysiology of schizophrenia (SZ) in both mice and humans. Yet, the precise mechanisms underlying sleep perturbations in SZ remain unclear. Here, we characterised the dynamics of thalamo-cortical networks across sleep-wake states in a mouse model carrying a mutation in the enzyme glutathione synthetase gene (Gclm-/-) associated with SZ in humans. We hypothesised that deficits in parvalbumin immunoreactive cells in the thalamic reticular nucleus (TRN) and the anterior cingulate cortex (ACC) -caused by oxidative stress - impact thalamocortical dynamics, thus affecting non-rapid eye movement (NREM) sleep and sleep homeostasis. Using polysomnographic recordings in mice, we showed that KO mice exhibited a fragmented sleep architecture, similar to SZ patients and altered sleep homeostasis responses revealed by an increase in NREM latency and slow wave activities during the recovery period (SR). Although NREM sleep spindle rate during spontaneous sleep was similar in Gclm-/- and Gcml +/+, KO mice lacked a proper homeostatic response during SR. Interestingly, using multisite electrophysiological recordings in freely-moving mice, we found that high order thalamic network dynamics showed increased synchronisation, that was exacerbated during the sleep recovery period subsequent to extended wakefulness (SD), possibly due to lower bursting activity in TRN-antero dorsal thalamus circuit in KO compared to WT littermates. Collectively, these findings provide a mechanism for SZ associated deficits of thalamo-cortical neuron dynamics and perturbations of sleep architecture.

scholarly journals The therapeutic mechanism of epilepsy seizures in different target areas: Research on a theoretical model

2021 ◽  
Vol 29 ◽  
pp. 455-461
Author(s):  
Bing Hu ◽  
Zhizhi Wang ◽  
Minbo Xu ◽  
Luyao Zhu ◽  
Dingjiang Wang
Keyword(s):  
Pyramidal Neurons ◽  
Control Mechanism ◽  
Difficult Problem ◽  
Calculation Model ◽  
Thalamic Reticular Nucleus ◽  
Reticular Nucleus ◽  
Theoretical Support ◽  
Therapeutic Mechanism ◽  
Optimal Target ◽  
Selection Of

BACKGROUND: The selection of optimal target areas in the surgical treatment of epilepsy is always a difficult problem in medicine. OBJECTIVE: We employed a theoretical calculation model to explore the control mechanism of seizures by an external voltage stimulus acting in different nerve nuclei. METHODS: Theoretical analysis and numerical simulation were combined. RESULTS: The globus pallidus, excitatory pyramidal neurons, striatal D1 neurons, thalamic reticular nucleus and specific relay nuclei were selected, we analyzed that the electrical stimulation has different effects in these target areas. CONCLUSIONS: The data selected were reasonable in study, the results may give a theoretical support for similar studies in clinical.

scholarly journals Synaptic properties of the feedback connections from the thalamic reticular nucleus to the dorsal lateral geniculate nucleus

2020 ◽  
Vol 124 (2) ◽  
pp. 404-417 ◽  
Author(s):  
Peter W. Campbell ◽  
Gubbi Govindaiah ◽  
Sean P. Masterson ◽  
Martha E. Bickford ◽  
William Guido
Keyword(s):  
Lateral Geniculate Nucleus ◽  
Dorsal Lateral Geniculate Nucleus ◽  
Thalamic Reticular Nucleus ◽  
Reticular Nucleus ◽  
Lateral Geniculate ◽  
Dependent Form ◽  
Dorsal Lateral Geniculate ◽  
Feedback Connections ◽  
Spike Firing ◽  
Stimulation Of

The thalamic reticular nucleus (TRN) modulates thalamocortical transmission through inhibition. In mouse, TRN terminals in the dorsal lateral geniculate nucleus (dLGN) form synapses with relay neurons but not interneurons. Stimulation of TRN terminals in dLGN leads to a frequency-dependent form of inhibition, with higher rates of stimulation leading to a greater suppression of spike firing. Thus, TRN inhibition appears more dynamic than previously recognized, having a graded rather than an all-or-none impact on thalamocortical transmission.

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