The hypothesis that nucleus reticularis thalami (RE) is the generator of spindle rhythmicity during electroencephalogram (EEG) synchronization was tested in acutely prepared cats. Unit discharges and focal waves were extracellularly recorded rostral pole RE nucleus, which completely disconnected by transections from all other thalamic nuclei. In some experiments, additional through corona radiata created a triangular island survived with caudate putamen, basal forebrain nuclei, prepyriform...

The effects of depriving thalamic relay and intralaminar nuclei from their reticularis thalami (RE) inputs were investigated in acute chronic experiments on cat. In acutely prepared animals, two (frontal parasagittal) transections made; extracellular intracellular recordings performed RE-disconnected nuclei. experiments, the RE nuclear complex was lesioned by means kainic acid injections; activity RE-deprived thalamocortical neurons extracellularly studied during wakefulness synchronized...

Intracellular and extracellular recordings were performed in lateral thalamic nuclei (ventroanterior-ventrolateral, ventroposterolateral, centralis, lateralis, reticularis) of cats under barbiturate anesthesia. Neurons driven antidromically and/or synaptically by stimulating cortical projection areas prethalamic afferent pathways. Three neuronal populations identified on the basis electrophysiological anatomical criteria: relay neurons, local interneurons, reticularis thalami neurons. At...

1. Intracellularly recorded low- and high-frequency (4-6 25-50 Hz, respectively), rhythmic, spontaneous membrane potential oscillations were investigated in pyramidal neurons of the rat hippocampus vivo, during theta (theta, 4-6 Hz) electroencephalographic (EEG) activity, under ketamine-xylazine anesthesia. 2. The EEG activity showed two spectral peaks, one range, other at higher frequencies (25-50 Hz). On basis their electrophysiological pharmacological properties, it was concluded that...

Abstract This study investigated the pattern of axonal projections single corticothalamic neurons from cortical barrel field representing vibrissae in rat. Microiontophoretic injections biocytin were performed layers V and VI to label small pools cells their intrathalamic projections. After a survival period 48 h, animals perfused tissue was processed for histochemistry. On basis distribution fields types terminations found thalamus, four identified, (i) Cells upper part layer projected...

Ascending and descending information is relayed through the thalamus via strong, "driver" pathways. According to our current knowledge, different driver pathways are organized in parallel streams do not interact at thalamic level. Using an electron microscopic approach combined with optogenetics vivo physiology, we examined whether inputs arising from sources can single thalamocortical cells rodent somatosensory (nucleus posterior, POm). Both anatomical physiological data demonstrated that...

A sample of 84 neurons in lamina VIa rat somatosensory cortex (S1) was juxtacellularly labeled with biocytin, and the axons were traced. Three classes cells identified as corticothalamic, corticocortical, local circuit neurons. Corticothalamic (46%) are small, short pyramids projecting either to ventral posteromedial nucleus alone or posterior group well. The former upper VI, have apical dendrites terminating layer IV, intracortical collaterals ascending IV a narrow column about size barrel....

Reticularis thalami neurons (RE neurons) were identified morphologically, and their electrophysiological properties studied in cat under barbiturate anesthesia. Intracellular HRP injections showed that RE possessed very long dendrites bearing numerous filopodia-like appendages axons directed toward main thalamic nuclei. As a rule, small axonal branches also emitted within the nucleus itself. At rest, membrane potential of displayed 2 types oscillations: slow 0.1–0.2 Hz oscillation fast 7–12...

This study investigated the organization of a vibrissal pathway that arises from interpolar division spinal trigeminal complex (SP5i), transits through ventral posterior medial nucleus (VPM), and innervates somatosensory cortical areas in rat. Using Fluoro-Gold biotinylated dextran amine, respectively, as retrograde anterograde tracers, following plan was disclosed. The SP5i projection population small-sized neurons selectively innervate lateral part VPM. In cytochrome oxidase-stained...

Though most experimental evidence indicates that the corticothalamic (CT) pathway would exert a direct excitatory action on thalamic relay neurons, electrophysiological features of this excitation have never been clearly described. A methodological problem in previous studies was corticofugal effects cells could not be separated from those mediated by collateral activation reticular neurons. In present study, complex lesioned kainic acid and CT response neurons ventral lateral nucleus...

Sensory stimuli evoke strong responses in thalamic relay cells, which ensure a faithful of information to the neocortex. However, cells posterior nuclear group rodents, despite receiving significant trigeminal input, respond poorly vibrissa deflection. Here we show that sensory transmission this nucleus is impeded by fast feedforward inhibition mediated GABAergic neurons zona incerta. Intracellular recordings revealed first synaptic event after whisker deflection prominent inhibition....

Abstract Thalamostriatal projections arising from the posterior intralaminar nuclei (Pl; parafascicular nucleus and adjacent caudalmost part of thalamic group) were studied in rats by tracing axons small pools neurons labelled anterogradely with biocytin. Thirteen Pl cells also stained juxtacellular application tracer. Relay have a morphology that differs radically classical descriptions bushy which represent main neuronal type sensory relay nuclei. ovoid or polygonal somata ˜20–25 μm,...

Intracellular recordings were performed in the lateral thalamic nuclei of cats under barbiturate anesthesia. The nature cyclic hyperpolarizations triggered relay cells by cortical stimulation was analyzed. These long-lasting made three different components. early component, which reversed current and Cl injections, identified as a Cl-dependent inhibitory postsynaptic potential (IPSP). A depolarizing hump usually present depth hyperpolarization. This intermediate component voltage-dependent...

Abstract The intracortical arborizations of neurons from the ventroposterolateral thalamic nucleus (VPL) in cat were studied by intraaxonal injections horseradish peroxidase (HRP) following identification their receptive fields. In primary somatic sensory cortex (SI) VPL cells terminated different cytoarchitectonic areas according to field modality. Fibers excited deep tissues or joint rotation arborized preferentially area 3a. Those responding tonically cutaneous stimuli located anterior...