Functional Diversity of Thalamic Reticular Subnetworks.

The activity of the GABAergic neurons of the thalamic reticular nucleus (TRN) has long been known to play important roles in modulating the flow of information through the thalamus and in generating changes in thalamic activity during transitions from wakefulness to sleep. Recently, technological advances have considerably expanded our understanding of the functional organization of TRN. These have identified an impressive array of functionally distinct subnetworks in TRN that participate in sensory, motor, and/or cognitive processes through their different functional connections with thalamic projection neurons.

GABAA , NMDA and mGlu2 receptors tonically regulate inhibition and excitation in the thalamic reticular nucleus.

Traditionally, neurotransmitters are associated with a fast, or phasic, type of action on neurons in the central nervous system (CNS). However, accumulating evidence indicates that γ-aminobutyric acid (GABA) and glutamate can also have a continual, or tonic, influence on these cells. Here, in voltage- and current-clamp recordings in rat brain slices, we identify three types of tonically active receptors in a single CNS structure, the thalamic reticular nucleus (TRN).

Two differential frequency-dependent mechanisms regulating tonic firing of thalamic reticular neurons.

Transmission through the thalamus activates circuits involving the GABAergic neurons of the thalamic reticular nucleus (TRN). TRN cells receive excitatory inputs from thalamocortical and corticothalamic cells and send inhibitory projections to thalamocortical cells. The inhibitory output of TRN neurons largely depends on the level of excitatory drive to these cells but may also be partly under the control of mechanisms intrinsic to the TRN.

Developmental changes in AMPA and kainate receptor-mediated quantal transmission at thalamocortical synapses in the barrel cortex.

During the first week of life, there is a shift from kainate to AMPA receptor-mediated thalamocortical transmission in layer IV barrel cortex. However, the mechanisms underlying this change and the differential properties of AMPA and kainate receptor-mediated transmission remain essentially unexplored. To investigate this, we studied the quantal properties of AMPA and kainate receptor-mediated transmission using strontium-evoked miniature EPSCs.

New intrathalamic pathways allowing modality-related and cross-modality switching in the dorsal thalamus.

Transmission through the dorsal thalamus involves nuclei that convey different aspects of sensory or motor information. Cells in the dorsal thalamus are strongly inhibited by the GABAergic cells of the thalamic reticular nucleus (TRN). Here we show that stimulation of cells in specific dorsal thalamic nuclei evokes robust IPSCs or IPSPs in other specific dorsal thalamic nuclei and vice versa.

A presynaptic kainate receptor is involved in regulating the dynamic properties of thalamocortical synapses during development.

Previous studies have shown that pharmacological activation of presynaptic kainate receptors at glutamatergic synapses facilitates or depresses transmission in a dose-dependent manner. However, the only synaptically activated kainate autoreceptor described to date is facilitatory. Here, we describe a kainate autoreceptor that depresses synaptic transmission.

The Somatotopic Organization Within the Cat's Thalamic Reticular Nucleus.

The organization of the somatosensory representation within the cat's thalamic reticular nucleus (TRN) was studied. Focal injections of horseradish peroxidase (HRP), wheatgerm agglutinin conjugated to HRP, and/or [3H]proline were made into somatosensory cortical areas 1 (S1) and 2 (S2). The resultant labelling in the thalamus was analysed.

The Somatotopic Organization Within the Rabbit's Thalamic Reticular Nucleus.

The organization of the somatosensory representation within the rabbit's thalamic reticular nucleus (TRN) was studied. Focal injections of horseradish peroxidase (HRP), wheatgerm agglutinin conjugated to HRP, or [3H]proline were made into somatosensory cortical area 1 (S1). The resultant labelling in the thalamus was analysed.

The Topographic Organization and Axis of Projection within the Visual Sector of the Rabbit's Thalamic Reticular Nucleus.

The organization of the visual field representation within the thalamic reticular nucleus (TRN) of the rabbit was studied. Focal injections of horseradish peroxidase (HRP) and/or [3H]proline were made into visuocortical areas V1 and V2 and the dorsal lateral geniculate nucleus (dLGN). The resultant labelling in the thalamus was analysed.