Biomaterial Database

Physiological characteristics of anterior thalamic nuclei, a group devoid of inputs from reticular thalamic nucleus. 1987

D Paré, and M Steriade, and M Deschênes, and G Oakson

This study tested the hypothesis that neurons of thalamic nuclei, which are normally devoid of inputs from the reticular thalamic nucleus, do not display spindle oscillations and related rhythmic spike bursts. This proposal derived from our recent studies indicating that the reticular nucleus is the generator of spindling rhythmicity. We used retrograde tracing methods, intracellular recordings in barbiturized cats, and extracellular recordings of single neurons and field potentials in anteroventral (AV), anteromedial (AM), ventroanterior (VA), ventrolateral (VL), and central lateral (CL) thalamic nuclei in cats with rostral brain stem transections (cerveau isolé preparations), before and after administration of barbiturates. The observation that AV and AM nuclei do not receive inputs from the reticular nucleus was confirmed by using injections of horseradish peroxidase conjugated to wheat germ agglutinin confined within the limits of anterior nuclei. Such injections led to massive retrograde labeling in mammillary nuclei and layer VI of the retrosplenial cortex but left free of labeling the neurons of the reticular thalamic nucleus. Intracellular recordings showed that AV-AM neurons discharge tonically in response to a depolarizing current applied at rest, whereas they give rise to a slow spike that underlies a burst of fast action potentials when the membrane is hyperpolarized by 5-12 mV. Despite the fact that they share similar properties with other thalamic neurons, intracellularly recorded AV-AM neurons do not exhibit spindle waves under barbiturate anesthesia, whereas VA-VL, CL, and other thalamocortical neurons that receive afferents from the reticular nucleus commonly display such oscillations. With extracellular recordings performed simultaneously in CL and AV or AM nuclei of the unanesthetized cerveau isolé preparation, focal spindle oscillations and related rhythmic high-frequency spike bursts of single CL cells contrasted with absence of spindles and spike bursts in AV or AM neurons. Spindling could be induced in AV-AM nuclei only after administration of barbiturates at doses exceeding 3 mg/kg, and it appeared approximately 35-40 s after the barbiturate effect was detected in the simultaneously recorded CL nucleus. Moreover, the spike bursts that were elicited in AV-AM neurons after barbiturate administration were not temporally related with focal spindles. Since spindle oscillations did not appear intracellularly in AV-AM neurons, the possibility was envisaged that barbiturate-induced spindles were the passive reflection of field potentials actively generated in neighboring thalamic nuclei.(ABSTRACT TRUNCATED AT 400 WORDS)

UI	MeSH Term	Description	Entries
D008297	Male		Males
D008326	Mammillary Bodies	A pair of nuclei and associated GRAY MATTER in the interpeduncular space rostral to the posterior perforated substance in the POSTERIOR HYPOTHALAMUS.	Mamillary Bodies,Bodies, Mamillary,Bodies, Mammillary,Body, Mamillary,Body, Mammillary,Mamillary Body,Mammillary Body
D008564	Membrane Potentials	The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).	Resting Potentials,Transmembrane Potentials,Delta Psi,Resting Membrane Potential,Transmembrane Electrical Potential Difference,Transmembrane Potential Difference,Difference, Transmembrane Potential,Differences, Transmembrane Potential,Membrane Potential,Membrane Potential, Resting,Membrane Potentials, Resting,Potential Difference, Transmembrane,Potential Differences, Transmembrane,Potential, Membrane,Potential, Resting,Potential, Transmembrane,Potentials, Membrane,Potentials, Resting,Potentials, Transmembrane,Resting Membrane Potentials,Resting Potential,Transmembrane Potential,Transmembrane Potential Differences
D008723	Methohexital	An intravenous anesthetic with a short duration of action that may be used for induction of anesthesia.	Methohexitone,Brevimytal Natrium,Brevital,Brietal,Brietal-Sodium,Methohexital Sodium,Methohexital, Monosodium Salt,Brietal Sodium,Monosodium Salt Methohexital,Natrium, Brevimytal,Sodium, Methohexital
D009434	Neural Pathways	Neural tracts connecting one part of the nervous system with another.	Neural Interconnections,Interconnection, Neural,Interconnections, Neural,Neural Interconnection,Neural Pathway,Pathway, Neural,Pathways, Neural
D009435	Synaptic Transmission	The communication from a NEURON to a target (neuron, muscle, or secretory cell) across a SYNAPSE. In chemical synaptic transmission, the presynaptic neuron releases a NEUROTRANSMITTER that diffuses across the synaptic cleft and binds to specific synaptic receptors, activating them. The activated receptors modulate specific ion channels and/or second-messenger systems in the postsynaptic cell. In electrical synaptic transmission, electrical signals are communicated as an ionic current flow across ELECTRICAL SYNAPSES.	Neural Transmission,Neurotransmission,Transmission, Neural,Transmission, Synaptic
D002415	Cats	The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)	Felis catus,Felis domesticus,Domestic Cats,Felis domestica,Felis sylvestris catus,Cat,Cat, Domestic,Cats, Domestic,Domestic Cat
D002540	Cerebral Cortex	The thin layer of GRAY MATTER on the surface of the CEREBRAL HEMISPHERES that develops from the TELENCEPHALON and folds into gyri and sulci. It reaches its highest development in humans and is responsible for intellectual faculties and higher mental functions.	Allocortex,Archipallium,Cortex Cerebri,Cortical Plate,Paleocortex,Periallocortex,Allocortices,Archipalliums,Cerebral Cortices,Cortex Cerebrus,Cortex, Cerebral,Cortical Plates,Paleocortices,Periallocortices,Plate, Cortical
D003655	Decerebrate State	A condition characterized by abnormal posturing of the limbs that is associated with injury to the brainstem. This may occur as a clinical manifestation or induced experimentally in animals. The extensor reflexes are exaggerated leading to rigid extension of the limbs accompanied by hyperreflexia and opisthotonus. This condition is usually caused by lesions which occur in the region of the brainstem that lies between the red nuclei and the vestibular nuclei. In contrast, decorticate rigidity is characterized by flexion of the elbows and wrists with extension of the legs and feet. The causative lesion for this condition is located above the red nuclei and usually consists of diffuse cerebral damage. (From Adams et al., Principles of Neurology, 6th ed, p358)	Decerebrate Posturing,Decorticate Rigidity,Decorticate State,Rigidity, Decerebrate,Rigidity, Decorticate,Decerebrate Posturings,Decerebrate Rigidity,Decerebrate States,Decorticate Rigidities,Decorticate States,Posturing, Decerebrate,Posturings, Decerebrate,Rigidities, Decorticate,State, Decerebrate,States, Decerebrate
D004594	Electrophysiology	The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.