Synaptic activation of the group I metabotropic glutamate receptor mGlu1 on the thalamocortical neurons of the rat dorsal Lateral Geniculate Nucleus in vitro

Turner, J. P.; Salt, Te

doi:10.1016/s0306-4522(00)00280-3

Cited by 49 publications

(48 citation statements)

References 56 publications

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“…2Dii). These data largely confirm those of Turner and Salt (2000) for layer 6 inputs to the lateral geniculate nucleus in the rat. The highfrequency stimulation (Ն100 Hz) was performed at relatively depolarized membrane potentials to avoid activation of lowthreshold Ca 2ϩ currents that are prominent in thalamic neurons and not easily blocked by pharmacological means.…”

Section: Synaptic Inputs To Cells Of the Lateral Geniculate Nucleussupporting

confidence: 83%

Somatosensory Corticothalamic Projections: Distinguishing Drivers From Modulators

Reichova

Sherman

2004

Journal of Neurophysiology

244

291

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. We used a juvenile mouse thalamocortical slice preparation with whole cell recording to investigate synaptic properties of corticothalamic inputs from somatosensory cortex to the ventral posterior medial and posterior medial nuclei (98 cells). We compared these data to those obtained from activating retinal and cortical inputs to the lateral geniculate nucleus (8 cells), the former representing a prototypical driver input and the latter, a typical modulator. Retinogeniculate activation evoked large, all-or-none excitatory postsynaptic potentials (EPSPs) that showed paired-pulse depression antagonized by N-methyl-D-aspartate (NMDA) and AMPA receptor blockers but with no sign of a metabotropic glutamate receptor (mGluR) component. Corticogeniculate activation evoked small, graded EPSPs showing paired-pulse facilitation, and the EPSPs showed both NMDA and AMPA receptor component plus an mGluR1 component. In the somatosensory thalamic relays, cortical stimulation elicited glutamatergic EPSPs in all thalamic cells, and these EPSPs fell into two groups. One, elicited from cortical layer 6 to cells of both nuclei, involved small, graded EPSPs with paired-pulse facilitation, and most also showed an mGluR1 component. The other, elicited from layer 5 to cells only of the posterior medial nucleus, involved large, all-ornone EPSPs with paired-pulse depression, and none showed an mGluR component. By analogy with results from the lateral geniculate nucleus, we conclude that the input from layer 6 to both nuclei acts as a modulator but that the layer 5 input to the posterior medial nucleus serves as a driver. Our data extend a common organizing principle from first-order nuclei to higher-order thalamic relays and further implicate the latter in corticocortical communication. I N T R O D U C T I O NGuillery and Sherman have recently proposed that thalamic relays can be divided into two types: first order and higher order Sherman and Guillery 2001, 2002). First-order relays represent the first transmission to cortex of particular type of information from the periphery, and higher-order relays serve to transmit information between cortical areas via a cortico-thalamo-cortical route. Examples of the former are the lateral geniculate nucleus for vision (relaying retinal input) and the ventral posterior nucleus for somesthesis (relaying medial lemniscal input); examples of the latter are most or all of pulvinar for vision and the posterior medial nucleus for somesthesis.A key to this hypothesis is identifying the information actually relayed through thalamus. To do so, Guillery and Sherman have divided inputs to relay cells into drivers, which bring the information to be relayed, and modulators, which serve to modulate thalamic transmission of the driver input (Sherman and Guillery 1998, 2001). Examples of the former are the retinal and medial lemniscal input to the lateral geniculate nucleus and ventral posterior nucleus, respectively. Examples of the latter are brain stem cholinergic inputs from the parabrachial region and feed...

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Section: Synaptic Inputs To Cells Of the Lateral Geniculate Nucleussupporting

confidence: 83%

Somatosensory Corticothalamic Projections: Distinguishing Drivers From Modulators

Reichova

Sherman

2004

Journal of Neurophysiology

244

291

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“…ACPD-induced rhythmicity has been reported for other systems, in particular the hippocampus (Whittington et al, 1995) and neocortex (Beierlein et al, 2000;Deans et al, 2001). Furthermore, evoked rhythms of ϳ8 -15 Hz follow mGluR activation of cat thalamic relay neurons in vitro (Hughes et al, 2002), caused in part by a decrease in leak conductance leading to membrane depolarization and enhanced excitability (McCormick and von Krosigk, 1992;Turner and Salt, 2000). Regardless of its ionic mechanisms, our results suggest that modulator-induced alterations of TRN membranes may contribute significantly to the generation of spindle-frequency oscillations in the thalamus.…”

Section: Discussionmentioning

confidence: 90%

Small Clusters of Electrically Coupled Neurons Generate Synchronous Rhythms in the Thalamic Reticular Nucleus

Long¹,

Landisman²,

Connors³

2004

J. Neurosci.

175

168

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The inhibitory neurons of the thalamic reticular nucleus (TRN) contribute to the generation of widespread oscillations in the thalamocortical system. Some TRN neurons are interconnected by electrical synapses, and here we tested the possibility that electrical synapses mediate rhythmic synchrony in juvenile rats. Both the incidence and strength of electrical coupling between pairs of TRN neurons were a steep function of intersomatic distance, and coupling was absent at distances Ͼ40 m. Presynaptic spike bursts evoked much larger electrical postsynaptic potentials than did single presynaptic spikes. Activation of metabotropic glutamate receptors (mGluRs) with a bath-applied agonist or an endogenous ligand released during tetanic stimulation induced robust rhythms of the subthreshold membrane potential, with a mean frequency of ϳ10 Hz. In the absence of fast chemical synaptic transmission, subthreshold rhythms and the action potentials that they evoked were well synchronized between closely spaced, electrically coupled pairs; rhythms in noncoupled cells were not synchronized. The results suggest that electrical synapses can coordinate spindle-frequency rhythms among small clusters of mGluR-activated TRN cells.

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“…It is likely that the facilitatory effects on the responses to small stimuli follow from direct synapses to the relay cells from overlying layer 6 feedback terminals and are mediated by the mGlu1 receptors associated with these terminals (McCormick and von Krosigk, 1992;Godwin et al, 1996;Turner and Salt, 2000). Previous work in the cat has indicated that mGlu1 receptor activation may enhance the response to receptive field center stimulation (Rivadulla et al, 2002).…”

Section: Discussionmentioning

confidence: 99%

Differential Feedback Modulation of Center and Surround Mechanisms in Parvocellular Cells in the Visual Thalamus

et al. 2012

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Many cells in both the central visual system and other sensory systems exhibit a center surround organization in their receptive field, where the response to a centrally placed stimulus is modified when a surrounding area is also stimulated. This can follow from laterally directed connections in the local circuit at the level of the cell in question but could also involve more complex interactions. In the lateral geniculate nucleus (LGN), the cells relaying the retinal input display a concentric, center surround organization that in part follows from the similar organization characterizing the retinal cells providing their input. However, local thalamic inhibitory interneurons also play a role, and as we examine here, feedback from the visual cortex too. Here, we show in the primate (macaque) that spatially organized cortical feedback provides a clear and differential influence serving to enhance both responses to stimulation within the center of the receptive field and the ability of the nonclassical surround mechanism to attenuate this. In short, both center and surround mechanisms are influenced by the feedback. This dynamically sharpens the spatial focus of the receptive field and introduces nonlinearities from the cortical mechanism into the LGN.

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Synaptic activation of the group I metabotropic glutamate receptor mGlu1 on the thalamocortical neurons of the rat dorsal Lateral Geniculate Nucleus in vitro

Cited by 49 publications

References 56 publications

Somatosensory Corticothalamic Projections: Distinguishing Drivers From Modulators

Somatosensory Corticothalamic Projections: Distinguishing Drivers From Modulators

Small Clusters of Electrically Coupled Neurons Generate Synchronous Rhythms in the Thalamic Reticular Nucleus

Differential Feedback Modulation of Center and Surround Mechanisms in Parvocellular Cells in the Visual Thalamus

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