Cuneate nucleus

About: Cuneate nucleus is a research topic. Over the lifetime, 614 publications have been published within this topic receiving 24859 citations. The topic is also known as: cuneate nucleus of spinal cord.

GABA-A and GABA-B receptors in the cuneate nucleus of the rat in vivo

Abstract: Electric stimulation of the rat forepaw evokes a negative potential (N-wave) at the ipsilateral cuneate nucleus. The responses of the N-wave to microiontophoretically applied GABA agonists and antagonists have been studied. Applications of GABA-A agonists (3-amino-propanesulfonic acid and muscimol) reduce the amplitude of the N-wave. This effect decreases during prolonged application, suggesting a desensitization of GABA-A receptors. In addition the effect of muscimol is reduced by (-)-bicuculline methiodide. Baclofen (a GABA-B agonist) also depresses the N-wave but its action lasts longer, is less reversible, shows no desensitization and is not blocked by (-)-bicuculline methiodide. The different responses of the N-wave to GABA-A and GABA-B agonists are compatible with the existence of different types of functional receptors for them in the cuneate nucleus of the rat. The receptors activated by muscimol (GABA-A) are clearly not the same as the ones activated by baclofen (conceivably GABA-B).

Complex synapses in the medial cuneate nucleus of the cat.

Abstract: An electronmicroscopical study using an analysis of thin sections and experimental degeneration of the medial cuneate nucleus of the cat has revealed five types of axon terminals: (1) Relatively large axon terminals characterized by a population of large (45-60 nm) spheroid vesicles which are the terminals of the spinal afferents: (2) Small axon terminals - probably of local interneuronal source - containing characteristic flattened vesicles: (3) Small axon terminals, mostly of local source (probably relay cell axon collaterals or possibly interneurons) containing small spheroid vesicles. A few axon terminals with similar small spheroid vesicles are of (contralateral) cortical origin from the somatosensory area; (4) Medium size axon terminals containing pleomorphic (ovoid to round) vesicles and being of local source (probably from local or neighbouring interneurons); (5) Occasionally axon terminals containing large dense-core vesicles (100-120 nm) were also observed. While types (1), (2), (3) and (4) are presynaptic to dendrites and (less frequently) to cell bodies, type (2), (3) and (4) were observed to be presynaptic also (axo-axonally) to type (1). Section series revealed that such axo-axonal synapses are in fact always arranged in "triadic combination" having the general formula of: 1 leads to dendrite (or soma), 2 (or 3, or 4) leads to 1, and 2 (or 3 or 4) leads to dendrite (or soma); the arrow indicating the morphological polarity of the synapse. -Presynaptic dendrites forming dendritic synapses and occasionally engaged in reciprocal synapses were also found, but in view of their rarity are probably only of secondary significance.

Nuclear Architecture in the Medulla Oblongata of the Adult African Giant Pouched Rat (Cricetomys gambianus, Waterhouse - 1840) Arquitectura Nuclear en la Médula Oblonga de la Rata Gigante de Carillos Africana Adulta (Cricetomys gambianus, Waterhouse - 1840)

Abstract: Ayo, J. O.IBE, C. S.; ONYEANUSI, B. I.; HAMBOLU, J. O. & AYO, J. O. Nuclear architecture in the medulla oblongata of the adult Africangiant pouched rat (Cricetomys gambianus, Waterhouse - 1840). Int. J. Morphol., 29(2):382-388, 2011.SUMMARY: The architecture of cranial and non-cranial nerve nuclei in the medulla oblongata of the African giant pouched ratwas studied by means of light microscopy. Serial sections of the medulla oblongata, in coronal and saggital planes, were staine d with thecresyl fast violet and silver stains, respectively. Sections in the saggital plane were used as a guide, while coronal sections were used toidentify the nuclei in the rostrocaudal extent of the medulla oblongata. With the obex serving as the landmark, nuclei rostral and caudalto the obex were delineated. Cranial nerve nuclei whose architecture were defined were the motor nucleus of hypoglossal nerve, motornucleus of vagus nerve, cochlear nucleus, vestibular nucleus and nucleus ambiguus, while non-cranial nerve nuclei identified were theolivary nucleus, solitary tract nucleus, gracile nucleus, cuneate nucleus, spinal nucleus of trigeminal nerve, motor nucleus of corpustrapezoideum, lateral nucleus of reticular formation and gigantocellular nucleus. The olivary nucleus was the most prominent nucleus,while the solitary tract nucleus was faint, and thus, less developed. The rostrocaudal extent of the solitary tract nucleus, ol ivary nucleusand motor nucleus of hypoglossal nerve were 3.81 mm, 2.36 mm and 3.50 mm in length, respectively. The prominent olivary nucleus,pyramidal tract and vestibular nucleus are indicative of a good motor coordination and balance, while the poorly developed soli tary tractnucleus points to less efficient autonomic functions in this rodent. The present study will serve as a lead for future neuro-behaviouralstudies necessary for an effective domestication and adaptation of the African giant pouched rat.KEY WORDS: Cranial nerve nuclei; Non-cranial nerve nuclei; Medulla oblongata; Obex.

A Cuneate-Based Network and Its Application as a Spatio-Temporal Filter in Mobile Robotics

Abstract: This paper focuses on a cuneate-based network (CBN), a connectionist model of the cuneate nucleus that shows spatial and temporal filtering mechanisms. The circuitry underlying these mechanisms were analyzed in a previous study by means of a realistic computational model [9,10] of the cuneate. In that study we have used experimental data (intracellular and extracellular recordings) obtained in cat in vivo [2,3] to guide and test the model. The CBN is a high-level description of the realistic model that allows to focus on the functional features and hide biological details. To demonstrate the CBN capabilities we have applied it to solve a filtering problem in mobile robotics.