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J L Velayos

Publications and source records attributed to J L Velayos.

10 recordsLinked to original sources
PubMed1993

Nicotinamide-adenine dinucleotide phosphate diaphorase activity matches acetylcholinesterase-rich patches in the medial thalamic nuclei of the cat.

Patches of high nicotinamide-adenine dinucleotide phosphate diaphorase (NADPH-d) activity were found in the mediodorsal and midline thalamic nuclei of cats. These patches matched acetylcholinesterase (AChE)-rich patches within the medial thalamus, whereas other AChE-rich patches were NADPH-d negative. There were also patches of NADPH-d activity in the lateral habenula, but these did not match the AChE staining. These results suggest that the functional role of discrete thalamic regions may require the joint presence of AChE and NADPH-d enzymatic activities.

Acetylcholinesterase↗
PubMed1992

[Projections from lamina V of the cerebral cortex to the dorsomedial thalamic nucleus and neighboring nuclei].

The laminar projections from the cerebral cortex to the mediodorsal thalamic nucleus and adjacent thalamic nuclei were studied by means of the horseradish peroxidase (HRP) retrograde axonal transport method. A possible correlation was found between the connectivity arising from layer V of the cerebral cortex, and the rich-acetylcholinesterase (AChE) regions within the subcortical structures under study. This suggests the possibility that layer V of the cerebral cortex in Alzheimer's disease is initially affected and subsequently those rich-AChE subcortical regions with which it is connected.

Acetylcholinesterase↗
PubMed1989

Topographical organization of the projections from the reticular thalamic nucleus to the intralaminar and medial thalamic nuclei in the cat.

The topography of the projections from the reticular nucleus of the thalamus (RT) to the intralaminar and medial thalamic nuclei were studied in the cat by the method of retrograde transport of horseradish peroxidase (HRP). Single small injections of the enzyme were made in the different intralaminar nuclei--mediodorsal, ventromedial, midline, and habenular--and in anterior group nuclei. The location and density of the neuronal labeling in the different parts of the RT were studied in each case. Our results show that 1) after injections located in all the nuclei here studied, a consistent number of labeled neurons were found in the RT, except for the injections in the lateral habenula and the anterior thalamic nuclear complex, both of which did not label neurons in the RT. 2) Among the other thalamic nuclei here studied, the most medially situated receive less numerous RT projections than those most laterally located. 3) Injections in all the nuclei studied gave rise to a cellular labeling in the anterior sectors of the RT, except for the anterior nuclear group and the lateral habenula. The projections from the rostral pole of the RT were topographically mediolaterally organized. 4) The anterodorsal part of the pregeniculate sector of the RT projects upon the large-celled part of the lateral central nucleus and to a lesser extent upon the paracentral, centromedian, and ventromedial nuclei, the anterior part of the lateral central nucleus, and the lateral band of the mediodorsal nucleus. The posterodorsal part of the RT pregeniculate sector only projects to the large-celled part of the lateral central nucleus. The dorsal portion of the posteroventral part of the RT pregeniculate sector also projects upon the large-celled part of the lateral central nucleus; its ventral portion projects to the ventromedial nucleus, the posterior part of the paracentral nucleus, the lateral band of the mediodorsal nucleus, and the centromedian nucleus. 5) The infrageniculate sector of the RT projects to the posterior part of the ventromedial nucleus. A weaker projection to the large-celled part of the lateral central nucleus, the centromedian nucleus, and the lateral band of the mediodorsal nucleus was also observed. 6) The ventral lateral geniculate nucleus projects upon the large-celled part of the lateral central nucleus, the lateral band of the mediodorsal nucleus, and the ventromedial nucleus. All these findings suggest an important modulatory action of the RT on the activity of the thalamic nuclei considered here.

Animals↗
PubMed1989

[Organization of the projections of the cortex of the sulcus cruciatus to the centromedian and parafascicular nuclei in cats].

In order to study the HRP retrograde axonal transport, injections of horseradish peroxidase (HRP) were made in the centromedian and parafascicular nuclei of the cat. The centromedian nucleus receives more cortical projections than the parafascicular nucleus. After centromedian and parafascicular nuclei injections, retrograde labeling was more abundant in the ventral bank of the cruciate sulcus than in its dorsal bank. Area 4 projects preferentially to the centromedian nucleus. These projections arise mainly in sector gamma of area 4. Projections from area 6 a beta to the centromedian and parafascicular nuclei are slightly more numerous than those arising in 6 a alpha. Projections from the sectors of motor and premotor areas located in the depth of the cruciate sulcus are scanty. These projections, however, are mainly directed to the centromedian nucleus and the lateral portions of the parafascicular nucleus. Cortical neurons projecting to centromedian and parafascicular nuclei are mainly situated in the superficial and intermediate sublayers of layer V. Only scarce projections arise from neurons located in layer VI.

Animals↗
PubMed1985

Prosencephalic afferents to the mediodorsal thalamic nucleus.

The afferent projections from the prosencephalon to the mediodorsal thalamic nucleus (MD) were studied in the cat by use of the method of retrograde transport of horseradish peroxidase (HRP). Cortical and subcortical prosencephalic structures project bilaterally to the MD. The cortical afferents originate mainly in the ipsilateral prefrontal cortex. The premotor, prelimbic, anterior limbic, and insular agranular cortical areas are also origins of consistent projections to the MD. The motor cortex, insular granular area, and some other cortical association areas may be the source of cortical connections to the MD. The subcortical projections originate principally in the ipsilateral rostral part of the reticular thalamic nucleus and the rostral lateral hypothalamic area. Other parts of the hypothalamus, the most caudal parts of the thalamic reticular nucleus, the basal prosencephalic structures, the zona incerta, the claustrum, and the entopeduncular and subthalamic nuclei are also sources of projections to the MD. Distinct, but somewhat overlapping areas of the prosencephalon project to the three vertical subdivisions of MD (medial, intermediate, and lateral). The medial band of the MD receives a small number of prosencephalic projections; these arise mainly in the caudal and ventral parts of the prefrontal cortex. Cortical projections also arise in the infralimbic area, while subcortical projections originate in the medial part of the rostral reticular thalamic nucleus and lateral hypothalamic area. The intermediate band of the MD receives the largest number of fibers from the prosencephalon. These arise principally in the intermediate and dorsal part of the lateral and medial surface of the prefrontal cortex, the premotor cortex, and the prelimbic and agranular insular areas. Projections also originate in basal prosencephalic formations (preoptic area, Broca's diagonal band, substantia innominata, and olfactory tubercle), rostral reticular thalamic nucleus, and lateral hypothalamic area. A large number of prosencephalic structures also project to the lateral band of the MD. These are mainly the most dorsal and caudal parts of the lateral and medial surface of the prefrontal cortex, the premotor and motor cortices, and the prelimbic, anterior limbic, and insular areas. Projections arise also in the lateral rostral and caudal parts of the reticular thalamic nucleus, the zona incerta, the lateral and dorsal hypothalamic area, the claustrum, and the entopeduncular nucleus. These and previous results demonstrate a gradation in the afferent connections to the three subdivisions of the MD.(ABSTRACT TRUNCATED AT 400 WORDS)

Afferent Pathways↗
PubMed1982

Topographic organization of the brainstem afferents to the mediodorsal thalamic nucleus.

The afferent projections from the brainstem to the mediodorsal thalamic nucleus (MD) were studied in the cat, by means of retrograde transport of horseradish peroxidase. A topographical arrangement of these projections is described. The medial part of MD is the area of the nucleus which receives fewer afferents from the brainstem. After injections in this part, labeled neurons were observed mainly in the interpeduncular nucleus, the ventral tegmental area and the substantia nigra. After injections of HRP in the intermediate part of the MD, labeled cells were seen mainly in the interpeduncular nucleus, substantia nigra, dorsal and centralis superior raphe nuclei, dorsal tegmental nucleus, and coeruleus complex. Less conspicuous was the number of labeled cells in the central gray and the dorsolateral portion of the tegmentum of the mesencephalon and pons. After injections in the lateral part of MD, labeled neurons were observed mainly in the deep layers of the superior colliculus, central gray, the oral paramedian pontine reticular tegmentum, and the interpeduncular nucleus. Labeled cells were also observed in the substantia nigra, locus coeruleus, dorsal tegmental nucleus, cuneiform area, and the mesencephalic reticular formation. These findings show the MD as a thalamic link of three different groups of brain-stem structures projecting to different cortical areas with different functional significance.

Afferent Pathways↗
PubMed1975

[Effect of 6-hydroxydopamine intracerebrally injected on reproduction in rats (author's transl)].

The effect of 6-hydroxidopamine (6-OH-DA) --250 mug-- intracerebrally injected on rat ovulation has been studied. Administration of 6-OH-DA in the nucleus accumbens septi and its heigbhourhood, inhibited follicle rupture, causing ovarian cycles with leucocitary phases in nearly all cases. The ovaries present a deep lutteynitation. Administration of 6-OH-DA in the strio-hypothalamic tract gives rise to a estrogenic cycle and to a normal number of oocytes in the tubes. The study of the fibrillar degeneration leads us to assumption of a probable adrenergic connections of the nucleus accumbens septi with the lateral hypothalamic area, preoptic area and olfactory tubercule. The influence of the nucleus accumbens septi on the mechanisms of follicle rupture is stressed.

Animals↗