Synchronized Oscillations at α and θ Frequencies in the Lateral Geniculate Nucleus

Hughes, Stuart W.; Lőrincz, Magor L.; Cope, David W.; Blethyn, Kate L.; Kékesi, Katalin A.; Parri, H. Rheinallt; Juhász, Gábor; Crunelli, Vincenzo

doi:10.1016/s0896-6273(04)00191-6

Cited by 270 publications

(392 citation statements)

References 43 publications

(1 reference statement)

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“…Indeed, the particular effectiveness of electrical synapses at transmitting lowfrequency events (Landisman et al, 2002;Long et al, 2004) makes them ideally suited to this role. A similar scenario might also exist for TC neurons (Hughes et al, 2004), where electrical synapses are also present (Hughes et al, 2002b), raising the prospect that a certain degree of slow (Ͻ1 Hz) wave synchronization can occur locally in the thalamus.…”

Section: Discussionmentioning

confidence: 85%

Neuronal Basis of the Slow (<1 Hz) Oscillation in Neurons of the Nucleus Reticularis ThalamiIn Vitro

et al. 2006

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During deep sleep and anesthesia, the EEG of humans and animals exhibits a distinctive slow (Ͻ1 Hz) rhythm. In inhibitory neurons of the nucleus reticularis thalami (NRT), this rhythm is reflected as a slow (Ͻ1 Hz) oscillation of the membrane potential comprising stereotypical, recurring "up" and "down" states. Here we show that reducing the leak current through the activation of group I metabotropic glutamate receptors (mGluRs) with either trans-ACPD [(ϩ/Ϫ)-1-aminocyclopentane-trans-1,3-dicarboxylic acid] (50 -100 M) or DHPG [(S)-3,5-dihydroxyphenylglycine] (100 M) instates an intrinsic slow oscillation in NRT neurons in vitro that is qualitatively equivalent to that observed in vivo. A slow oscillation could also be evoked by synaptically activating mGluRs on NRT neurons via the tetanic stimulation of corticothalamic fibers. Through a combination of experiments and computational modeling we show that the up state of the slow oscillation is predominantly generated by the "window" component of the T-type Ca 2ϩ current, with an additional supportive role for a Ca 2ϩ -activated nonselective cation current. The slow oscillation is also fundamentally reliant on an I h current and is extensively shaped by both Ca 2ϩ -and Na ϩ -activated K ϩ currents. In combination with previous work in thalamocortical neurons, this study suggests that the thalamus plays an important and active role in shaping the slow (Ͻ1 Hz) rhythm during deep sleep.

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Section: Discussionmentioning

confidence: 85%

Neuronal Basis of the Slow (<1 Hz) Oscillation in Neurons of the Nucleus Reticularis ThalamiIn Vitro

et al. 2006

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“…Under control conditions, most TC neurons fired rarely and irregularly, but, when they did so, firing was predominantly of the low-threshold burst firing type (83.3%; n ϭ 5 of 6 units) (Fig. 7A 1 ,B) (Hughes et al, 2004). In contrast, units recorded in the presence of 50 nM GBZ predominantly exhibited tonic rather than low-threshold burst firing (94.4%; n ϭ 17 of 18 units) (Fig.…”

Section: Preferential Block or Enhancement Of The Tonic Current Modulmentioning

confidence: 91%

“…Physiological significance TC neurons can exhibit three modes of firing: low-threshold bursting driven by low-threshold Ca 2ϩ spikes; tonic firing consisting of repetitive single action potentials; and high-threshold bursting mediated by high-threshold, probably T-type channeldependent, Ca 2ϩ spikes (Jahnsen and Llinás, 1984;Crunelli et al, 1989;Hughes et al, 2004). Tonic and high-threshold bursting occur at relatively depolarized membrane potentials, whereas low-threshold bursting occurs at hyperpolarized membrane potentials, with a region of quiescent membrane potential in between.…”

Section: Properties Of the Tonic Gaba A Currentmentioning

confidence: 99%

GABA_AReceptor-Mediated Tonic Inhibition in Thalamic Neurons

Cope

Hughes²,

Crunelli³

2005

J. Neurosci.

283

342

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Tonic GABA A receptor-mediated inhibition is typically generated by ␦ subunit-containing extrasynaptic receptors. Because the ␦ subunit is highly expressed in the thalamus, we tested whether thalamocortical (TC) neurons of the dorsal lateral geniculate nucleus (dLGN) and ventrobasal complex exhibit tonic inhibition. Focal application of gabazine (GBZ) (50 M) revealed the presence of a 20 pA tonic current in 75 and 63% of TC neurons from both nuclei, respectively. No tonic current was observed in GABAergic neurons of the nucleus reticularis thalami (NRT). Bath application of 1 M GABA increased tonic current amplitude to ϳ70 pA in 100% of TC neurons, but it was still not observed in NRT neurons. In dLGN TC neurons, the tonic current was sensitive to low concentrations of the ␦ subunit-specific receptor agonists allotetrahydrodeoxycorticosterone (100 nM) and 4,5,6,7-tetrahydroisoxazolo[5,4-c]-pyridin-3-ol (THIP) (100 nM) but insensitive to the benzodiazepine flurazepam (5 M). Bath application of low concentrations of GBZ (25-200 nM) preferentially blocked the tonic current, whereas phasic synaptic inhibition was primarily maintained. Under intracellular current-clamp conditions, the preferential block of the tonic current with GBZ led to a small depolarization and increase in input resistance. Using extracellular single-unit recordings, block of the tonic current caused the cessation of low-threshold burst firing and promoted tonic firing. Enhancement of the tonic current by THIP hyperpolarized TC neurons and promoted burst firing. Thus, tonic current in TC neurons generates an inhibitory tone. Its modulation contributes to the shift between different firing modes, promotes the transition between different behavioral states, and predisposes to absence seizures.

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“…(3) Bursting thalamic relay neurons exert a rhythmic influence on thalamocortical modules in the theta frequency band (Hughes et al, 2004). The tight anatomical (Van Horn et al, 2000) and functional coupling between the thalamus and cortex is confirmed by the high theta coherence between the two (Fig.…”

Section: Mechanism Of Pd Symptomsmentioning

confidence: 95%

High Thalamocortical Theta Coherence in Patients with Parkinson's Disease

Sarnthein

Jeanmonod²

2007

J. Neurosci.

114

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Research investigating the pathophysiology of Parkinson's disease (PD) mostly focuses on basal ganglia dysfunction. However, the main output from the basal ganglia is via the thalamus, and corticothalamic feedback constitutes the primary source of synapses in the thalamus. We therefore focus on the thalamocortical interplay. During the surgical intervention in six patients, local field potentials (LFPs) were recorded from pallidal-recipient thalamic nuclei VA and VLa. Simultaneously, EEG was recorded from several sites on the scalp. The highest thalamocortical coherence was found in the theta frequency band (4 -9 Hz) with a mean peak frequency of 7.5 Hz. The magnitude of thalamocortical theta coherence was comparable to the magnitude of EEG coherence between scalp electrode pairs. Thalamocortical theta coherence reached 70% and was maximal with frontal scalp sites on both hemispheres. In the 13-20 Hz ␤ frequency band, maximal coherence was comparatively low but localized on the scalp ipsilateral to the site of thalamic LFP recording. The high thalamocortical coherence underlines the importance of thalamic function for the genesis of scalp EEG. We discuss the PD pathophysiology within the framework of dysrhythmic thalamocortical interplay, which has important consequences for the choice of therapeutic strategy in patients with severe forms of PD.

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Synchronized Oscillations at α and θ Frequencies in the Lateral Geniculate Nucleus

Cited by 270 publications

References 43 publications

Neuronal Basis of the Slow (<1 Hz) Oscillation in Neurons of the Nucleus Reticularis ThalamiIn Vitro

Neuronal Basis of the Slow (<1 Hz) Oscillation in Neurons of the Nucleus Reticularis ThalamiIn Vitro

GABA_AReceptor-Mediated Tonic Inhibition in Thalamic Neurons

High Thalamocortical Theta Coherence in Patients with Parkinson's Disease

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Synchronized Oscillations at α and θ Frequencies in the Lateral Geniculate Nucleus

Cited by 270 publications

References 43 publications

Neuronal Basis of the Slow (<1 Hz) Oscillation in Neurons of the Nucleus Reticularis ThalamiIn Vitro

Neuronal Basis of the Slow (<1 Hz) Oscillation in Neurons of the Nucleus Reticularis ThalamiIn Vitro

GABAAReceptor-Mediated Tonic Inhibition in Thalamic Neurons

High Thalamocortical Theta Coherence in Patients with Parkinson's Disease

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Product

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GABA_AReceptor-Mediated Tonic Inhibition in Thalamic Neurons