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Biomedical subjects

J L Price

Publications and source records attributed to J L Price.

At least 145 records · Page 8Linked to original sources
PubMed1982

The distribution of axon collaterals from the olfactory bulb and the nucleus of the horizontal limb of the diagonal band to the olfactory cortex, demonstrated by double retrograde labeling techniques.

Three different pairs of double retrograde axonal tracers have been used to study the distribution of axon collaterals from individual cells in the olfactory bulb and the nucleus of the horizontal limb of the diagonal band: (1) horseradish peroxidase (HRP) and tritiated apo-HRP (3H-HRP), (2) HRP and 125I-wheat germ agglutinin (I-WGA), and (3) the fluorochromes true blue (TB) and bisbenzimide (BB) or nuclear yellow (NY). With each combination of tracers, paired injections were made into different parts of the olfactory system, and the olfactory bulb and the nucleus of the diagonal band were examined for the presence and arrangement of cells labeled with one or both retrograde tracers. In the olfactory bulb both single and double retrogradely labeled mitral cells were found following injections in disparate parts of the olfactory cortex. Furthermore, no consistent pattern was found in the distribution of single- or double-labeled cells in the olfactory bulb; that is, the distribution of cells labeled from one area of the cortex was not consistently different from the distribution of cells labeled from other parts of the cortex. Therefore, it was concluded that individual mitral cells project to widely spaced parts of the olfactory cortex, and that there is no apparent correspondence between the location of a given cell in the olfactory bulb and the distribution of its axon in the cortex. In contrast to this, cells in the nucleus of the horizontal limb of the diagonal band were only rarely double-labeled from nonoverlapping injections into the olfactory cortex or olfactory bulb, although overlapping injections produced a high proportion of double-labeled cells. Cells which were single-labeled from different injection sites were extensively intermixed within the nucleus. Therefore, in this case it was concluded that individual cells projects to relatively restricted areas, although there was again no apparent correspondence between the position of a cell in the nucleus and the terminal field of its axon.

Animals↗
PubMed1982

The thalamo-cortical projection of the nucleus submedius in the cat.

The cortical projection of the nucleus submedius (Sm) was studied in the cat with the autoradiographic and horseradish peroxidase (HRP) methods. The results indicate that Sm projects topographically on to layer 3 of a distinct agranular cortical field that occupies the posterolateral gyrus proreus, the adjacent fundus of the rhinal sulcus, and the postero-ventral portion of the medial wall of the presylvian sulcus. This cortical field is denoted the ventrolateral orbital cortex (VLO), consonant with previous nomenclature in the rat (Krettek and Price, '77a). The more ventral part (VLO beta) is cytoarchitectonically distinct from the dorsal part (VLO alpha); the former receives input from the anterior part of Sm (Sma), while the latter receives input from the dorsal and ventral parts of Sm (Smd and Smv). A light input to superficial layer 1 of VLO probably also arises from Sm, and there may be an input to layers 5 and 6. The corticothalamic projection from VLO to Sm reciprocates the ipsilateral thalamocortical projection and also has a moderate contralateral component. A dense, subpial layer 1 input to VLO arises from cells of the ventromedial nucleus (VM) subjacent to Sm. The present experiments also indicate that clusters of cells in VM probably provide input to layer 3 of the cortex in the fundus of the presylvian sulcus, as well as area 6a beta in the lateral wall of the presylvian sulcus and the ventral bank of the cruciate sulcus. Results from the HRP experiments additionally indicate that VLO beta and the anteroventral (Smv) portion of VLO alpha are reciprocally connected with the ventral agranular insular cortex and the cingulate cortex, ipsilaterally, while the posterodorsal (Smd) portion of VLO alpha is instead connected wih specific portions of the somatosensory cortical areas bilaterally. All portions of VLO alpha appear to project to the ventrolateral periaqueductal gray. In light of the recent suggestion that Smd is involved with nociception (Craig and Burton, '81), the present results suggest that the related portion of VLO alpha may serve as a cortical representation for noxious stimuli.

Afferent Pathways↗
PubMed1981

Establishment of normal synaptic density in deafferented olfactory cortex.

The piriform cortex has been examined in rats following neonatal deafferentation produced by olfactory bulb removal. The denervated molecular layer of the piriform cortex grows to nearly its full adult thickness and the removal olfactory bulb axons are replaced by intracortical axons. The synaptic density of the molecular layer following this rearrangement is the same as that in the normal cortex.

Aging↗
PubMed1981

Features of mammorgraphically negative breast tumours.

Mammography is a highly sensitive and specific technique in the diagnosis of breast cancer, but some tumours show no radiological features of malignancy. A total of 9.3 per cent of 323 consecutive patients with operable breast cancer had negative mammographic reports, and the clinical radiological and pathological findings in these cases are compared with those in the mammographically diagnosed group. Misinterpretation of carcinoma as a benign lesion and diagnostic difficulties in the dense dysplastic breast were found to be the main causes of error.

Adult↗
PubMed1981

A causal model for turnover for nurses.

Longitudinal data on 1,091 registered nurses in seven hospitals were used to estimate a causal model of turnover in organizations. Total effects on turnover were found to be the greatest for four determinants: intent to stay, opportunity, general training, and job satisfaction. The relative importance of the determinants of turnover and the explanatory power of the model are presented and discussed.

Analysis of Variance↗
PubMed1981

An autoradiographic study of the projections of the central nucleus of the monkey amygdala.

The efferent connections of the central nucleus of the monkey amygdala have been studied using the autoradiographic method for tracing axonal projections. Small injections of 3H-amino-acids which are largely confined to the central nucleus lead to the labeling of several brainstem nuclei as far caudally as the spinomedullary junction. Specifically, in the forebrain, the central nucleus projects heavily to the bed nucleus of the stria terminalis, the basal nucleus of Meynert, the nucleus of the horizontal limb of the diagonal band, and more lightly to the substantia innominata and the preoptic area. In the hypothalamus, label is found over the dorsomedial nucleus, the perifornical region, the lateral hypothalamus, the supramammillary area, and most heavily in the paramammillary nucleus. In the thalamus, all components of the nucleus centralis medialis and the nucleus reuniens receive fibers from the central nucleus and there is a light projection to the medial pulvinar nucleus. In the mesencephalon, there is heavy labeling dorsal to the substantia nigra ad over the peripeduncular nucleus and lighter labeling within the substantia nigra pars compacta and the ventral tegmental area; the midbrain central gray is also labeled. More caudally, fibers from the central nucleus travel in the lateral tegmental reticular fields and contribute collaterals to the raphe nuclei, the cuneiform nucleus, and the central gray substance. Perhaps one of the heaviest terminal zones is the parabrachial region of the pons, both the lateral and the medial nuclei of which receive a prominent central nucleus projection. Only the ventral aspect of the adjacent locus coeruleus appears to receive a substantial input, but there is labeling also over the area of the nucleus subcoeruleus. Finally, there is heavy labeling around the dorsal motor nucleus of the vagus and over the parvocellular component of the nucleus of the solitary tract. A number of intra-amygdaloid connections between the basal and lateral nuclei of the amygdala and the central nucleus are also described. The present findings, taken together with recently reported widespread projections from the temporal association cortex to the amygdala, point out a potentially trisynaptic route between neocortical association regions and a variety of brainstem nuclei, many of which are related to autonomic function.

Afferent Pathways↗
PubMed1980

Separate neurons in the paraventricular nucleus project to the median eminence and to the medulla or spinal cord.

Double labeling experiments with the retrogradely transported fluorescent tracers bisbenzimide and True blue indicate that separate populations of cells in the paraventricular nucleus of the hypothalamus project to the median eminence and to the dorsomedial medulla or spinal cord in the rat. The cell populations giving rise to each projection are, however, at least partially intermixed in different parts of the nucleus.

Animals↗
PubMed1980

Cells of origin of the afferent fibers to the median eminence in the rat.

The cell bodies of origin of axons terminating in the median eminence have been identified by retrograde axonal transport of horseradish peroxidase (HRP) or 125I-wheat germ agglutinin (WGA). The tracers were injected into the median eminence by pressure and under direct visual control, using a ventral surgical approach. The retrogradely labeled cells are exclusively located within the hypothalamus. The most heavily labeled cells are parvocellular neurons in the arcuate nucleus, the periventricular area, the medial part of the paraventricular nucleus, and the rostral paraventricular nucleus; a few cells are also located in the rostral part of the preoptic area immediately lateral and dorsal to the organum vasculosum of the lamina terminalis (OVLT). Less heavily located cells are found in the magnocellular neurosecretory nuclei, including the lateral parts of the paraventricular and rostral paraventricular nuclei, the supraoptic nucleus, and the accessory magnocellular nuclei. Retrogradely labeled cells are not found in the ventromedial hypothalamic nucleus, except for a few lightly labeled cells in the posterior division of the nucleus. However, if the injected tracer spreads into the arcuate nucleus, labeled cells are present throughout the ventromedial nucleus. Labeled cells are not found in other parts of the hypothalamus, including lateral and posterior portions of the preoptic area, the anterior hypothalamic area, and the suprachiasmatic nucleus, or in catecholaminergic cell groups of the midbrain, pons, and medulla. Control injections of HRP into the posterior pituitary and the ventromedial nucleus produce patterns of cell labeling which are very distinct from that seen with injections into the median eminence. Following injections into the posterior pituitary, the cells of the magnocellular neurosecretory nuclei are all heavily labeled, but small cells in the parvocellular neuronal groups are not labeled. Direct injections into the ventromedial nucleus resulted in labeled cells in widespread parts of the hypothalamus, as well as in the bed nucleus of the stria terminalis and the lateral septum, in parts of the amygdaloid complex and the subiculum, and in several cell groups in the midbrain, pons, and medulla.

Afferent Pathways↗
PubMed1978

Association and commissural fiber systems of the olfactory cortex of the rat.

The association and commissural fiber systems arising in the olfactory cortical areas caudal to the olfactory peduncle (the piriform cortex, nucleus of the lateral olfactory tract, anterior cortical nucleus of the amygdala, periamygdaloid cortex and entorhinal cortex) have been studied utilizing horseradish peroxidase as both an anterograde and a retrograde axonal tracer. In the piriform cortex two sublaminae within layer II (IIa and IIb) layer III have been found to give rise to distinctly different projections. Retrograde cell labeling experiments indicate that the association fiber projection from layer IIb is predominatnly caudally directed, while the projection from layer III is predominantly rostrally directed. Cells in layer IIa project heavily to areas both caudal and rostral to the piriform cortex. The commissural fibers from the piriform cortex are largely restricted in their origin to layer IIb of the anterior part of the piriform cortex and in their termination on the contralteral side to the posterior part of the piriform cortex and adjacent olfactory cortical areas. A projection to the olfactory bulb has also been found to arise from cells in layers IIb and III of the ipsilateral piriform cortex, but not in layer IIa. In addition to those from the piriform cortex, association projections have also been found from other olfactory cortical areas. The nucleus of the lateral olfactory tract has a heavy bilateral projection to the medial part of the anterior piriform cortex and the lateral part of the olfactory tubercle (as well as a lighter projection to the olfactory bulb); both the anterior cortical nucleus of the amygdala and the periamygdaloid cortex project ipsilaterally to several olfactory cortical areas. The entorhinal cortex has been found to project to the medial parts of the olfactory tubercle and the olfactory peduncle. The olfactory tubercle is the only olfactory cortical area from which no association fiber systems (instrinsic or extrinsic) have been found to originate. A broad topographic organization exists in the distribution of the fibers from several of the olfactory areas. This is most obvious in the anterior part of the olfactory cortex, in which fibers from the more rostral areas (the anterior olfactory nucleus and the anterior piriform cortex) terminate in regions near the lateral olfactory tract, while those from more caudal areas (the posterior piriform cortex and the entorhinal cortex) terminate in areas further removed, both laterally and medially, from the tract. Projection to olfactory areas from the hypothalamus, thalamus, diagonal band, and biogenic amine cell groups have been briefly described.

Animals↗