scispace - formally typeset
Search or ask a question
Journal ArticleDOI

Efferent connections of the periaqueductal gray matter in the cat.

01 May 1970-The Journal of Comparative Neurology (Wiley Subscription Services, Inc., A Wiley Company)-Vol. 139, Iss: 1, pp 105-114
TL;DR: Electrolytic lesions were stereotaxically placed in the dorsal and ventral areas of the mesencephalic periaqueductal gray in the cat to avoid electrode damage.
Abstract: Electrolytic lesions were stereotaxically placed in the dorsal and ventral areas of the mesencephalic periaqueductal gray in the cat. A dorsal angular approach was made so that mechanical electrode damage was contralateral to the lesion, or a posterior approach through the fourth ventricle was employed to avoid electrode damage. The brains were sectioned coronally and sagittally and stained with a modifield Nauta-Gygax or Fink-Heimer stain. Degeneration from the dorsal lesions was chiefly in a radial pattern to the superior colliculus, inferior colliculus and mesencephalic reticular area. Also, fibers angled out of the dorsal gray, crossed the midline and joined the commissure of the superior colliculus, some taking a ventrolateral course through the colliculi and others running ventrally along the borders of the gray. Degeneration was traced caudally to the cuneiform nucleus and adjacent reticular area. Rostrally, fibers traveled in the dorsal longitudinal fasciculus to the pretectal area, lateral habenular nucleus and finally, the posterior hypothalamic area. Ventral lesions showed the same radial pattern of degeneration and fibers in the superior colliculus commissure. Caudally, fibers could be traced to the cuneiform nucleus, reticular area and inferior olive. The rostral course of fibers in the dorsal longitudinal fasciculus was similar, though there were additional connections with the ventral tegmental area of Tsai, the fields of Forel, and the parafascicular nucleus of the thalamus.
Citations
More filters
Journal ArticleDOI
TL;DR: Two hours following intraperitoneal injection, estradiol‐H3 is concentrated by cells in a system of limbic and hypothalamic structures, which agrees with previous autoradiographic conclusions and with biochemical results from cell fractionation experiments.
Abstract: Two hours following intraperitoneal injection, estradiol-H3 is concentrated by cells in a system of limbic and hypothalamic structures. Preoptic-hypothalamic nuclei containing estrogen-concentrating cells include the medial preoptic area, medial anterior hypothalamus, ventromedial nucleus, arcuate nucleus and ventral premammillary nucleus. Limbic structures include the medial and cortical nuclei of the amygdala, lateral septum, bed nucleus of the stria terminalis, diagonal band of Broca, olfactory tubercle, ventral hippocampus, and prepiriform and entorhinal cortex. Labelled cells were also found in the lateral and ventrolateral portions of the mesencephalic central grey. Compared to these regions, most other regions of the nervous system, including the spinal cord, have very small numbers of labelled cells, which are relatively weakly labelled, and are not found in regular, specific locations. The distribution of estrogen-concentrating cells determined with the present autoradiographic method agrees with previous autoradiographic conclusions and with biochemical results from cell fractionation experiments. The locations of estrogen-concentrating cells coincide in several brain regions with locations of estrogen-dependent neuroendocrine control mechanisms, as determined by brain implants, lesions, electrical stimulation, and electrophysiological recording. Moreover, experimental neuroanatomical studies have provided evidence for several pathways connecting regions which concentrate radioactive estradiol. Taken together, the evidence suggests a limbic-hypothalamic system of estrogen-concentrating neurons which participate in the control of mating behavior and of gonadotrophin release from the pituitary.

1,470 citations

Journal ArticleDOI
01 Oct 1977-Pain
TL;DR: Experimental approaches are resorted to which permit a detailed study of the interaction between narcotic analgetics and particular regions and/or functional systems within the central nervous system.
Abstract: Narcotics reduce the behavioral response to injury, while leaving unaffected the response to other stimuli. This effect could be due to a reduction of the central transmission of injury signals (modulation of sensory throughput) or to an effect on higher inte~ative levels concerned with stimulus recognition or stimulus interpretation ** . Since much of the functional capacity of the central nervous system and nearly every level of the neuraxis is involved in signal processing, observations limited to the effect of systemically administered narcotics on behavior will provide little information regarding the specific sites and mechanisms of action of narcotic analgetics. Investigators interested in these aspects of narcotic activity have therefore resorted to experimental approaches which permit a detailed study of the interaction between narcotic analgetics and particular regions and/or functional systems within the central nervous system. Recording of local electrical activity following systemic application of a narcotic does not specify where the narcotic is acting. Similarly local lesions or electrical stimulation can only indicate through which systems narcotics may act and do not reveal the causal chain between injury and pain. As a consequence of the inadequacies of these approaches, investigators have turned with increasing frequency to methods which permit the application of drugs directly to single neurons or circumscribed neuronal pools. The mi~roiontophoretic technic has provided much of our limited information concerning the direct effects of narcotic analgetics on neuronal activity. ~n~o~unately, the microiontophoretic stimulation of a single neuron usually is incapable of eliciting a detectable behavioral response. Therefore, even though many neurons can be tested for their individual sensitivities to suspected neurotransmitter or other agents, it cannot be determined by ionto-

653 citations

Journal ArticleDOI
TL;DR: The organization of the regional connections was outlined in a stereotaxic atlas using the autoradiographic tracing method: the majority of the ascending pathways from the rostral raphe nuclei are directed mainly through a ventrolateral bundle via the ventral tegmental area of Tsai, with some lateral extensions to the substantia nigra, and then through the fields of Forel and the zona incerta.

652 citations

Journal ArticleDOI
TL;DR: In this article, a preliminary attempt is made to analyze the intraspecific aggressive behavior of mammals in terms of specific neural circuitry, and it is suggested that motivating stimuli activate pathways that converge upon sets of homogeneous neurons, called motivational mechanisms, whose activity determines the motivational state of the animal.
Abstract: A preliminary attempt is made to analyze the intraspecific aggressive behavior of mammals in terms of specific neural circuitry. The results of stimulation, lesion, and recording studies of aggressive behavior in cats and rats are reviewed and analyzed in terms of three hypothetical motivational systems: offense, defense, and submission. A critical distinction, derived from ethological theory, is made between motivating stimuli that simultaneously activate functional groupings of motor patterning mechanisms, and releasing and directing stimuli that are necessary for the activation of discrete motor patterning mechanisms. It is suggested that motivating stimuli activate pathways that converge upon sets of homogeneous neurons, called motivational mechanisms, whose activity determines the motivational state of the animal.A defense motivational mechanism is hypothesized to be located in the midbrain central gray. In addition to tactile, auditory, and visual inputs from the paleospinothalamic tract, lateral lemniscus, and (perhaps) from the pretectum, it may receive inputs from a major forebrain pathway whose functional significance is not yet understood.A submission motivational mechanism is also thought to be located in the central gray. In addition to inputs for defense, it is thought to receive a necessary input from a “consociate (social familiarity cue) modulator” located in the ventromedial hypothalamus, which can switch behavior from defense to submission. The location of the hypothetical offense motivational mechanism is not known, although the pathways by which it is activated are traced in some detail.Brain mechanisms of aggression in primitive mammals and in primates are apparently similar to those in rats and cats.

403 citations

Journal ArticleDOI
TL;DR: The results suggest that the dorsolateral and ventrolateral parts of the PAG are organized into longitudinal columns that extend throughout the length of the C5 noradrenergic cell group.
Abstract: The descending projections of the periaqueductal gray (PAG) have been studied in the rat using the anterograde tracer Phaseolus vulgaris-leucoagglutinin. The tracer was injected into the dorsolateral or ventrolateral subdivisions of the PAG at rostral or caudal sites. It was found that the patterns of the descending projections of the rostral and caudal parts of the dorsolateral PAG were the same and that the patterns of the descending projections of the rostral and caudal parts of the ventrolateral PAG were the same. However, the patterns of projections of the dorsolateral and ventrolateral PAG subregions were substantially different. These results suggest that the dorsolateral and ventrolateral parts of the PAG are organized into longitudinal columns that extend throughout the length of the PAG. The axons of PAG neurons descended through the pons and medulla via two routes. A small fiber bundle was present in the periaqueductal gray and in the periventricular area. This bundle distributed fibers and terminals locally within the periaqueductal gray and in the locus coeruleus and Barrington's nucleus. A larger bundle had a diffuse arrangement in the pontine reticular formation, however, and it had a more restricted distribution in the medulla, where it occupied a position dorsolateral to the pyramid. This bundle supplied structures in the pontine and medullary tegmentum. The dorsolateral column preferentially supplied the locus coeruleus, subcoeruleus, the gigantocellular nucleus pars alpha, the rostral part of the paragigantocellular nucleus, and the region of the A5 noradrenergic cell group. The ventrolateral column preferentially supplied the nucleus raphe magnus, the caudal part of the lateral paragigantocellular nucleus, and the rostroventrolateral reticular nucleus. © 1995 Willy-Liss, Inc.

349 citations

References
More filters
Journal ArticleDOI
TL;DR: The original, non-suppressive Natua method for impregenation of terminal degeneration has been modified by the introduction of a potassium permanganate-uranyl nitrate sequence, resulting in a selective impregnation of degenarated axons inclusive of their synaptic thickenings.

1,669 citations

Book
01 Jan 1968
TL;DR: This slim (73 text pages) volume stresses the "integrating functions of the vagi" in discussing vagal influences on the cardiovascular, respiratory, and gastrointestinal systems.
Abstract: Vagi in Medicine and Surgery. By George W. Holt, MD. Price, $6.75. Pp 92. Charles C Thomas, Publisher, 301-327 E Lawrence Ave, Springfield, Ill 62703, 1968. Physicians in many specialities deal with physiological and disease processes affected by, or inflicted by, the vagus nerves. In this slim (73 text pages) volume, the author stresses the "integrating functions of the vagi" in discussing vagal influences on the cardiovascular, respiratory, and gastrointestinal systems. Additional very brief sections

1,253 citations

Journal ArticleDOI
01 Sep 1958-Brain
TL;DR: Recent studies in the rat have confirmed much earlier descriptions of widespread distributions of the fornix system to the diencephalon and the rostral mid-brain regions.
Abstract: Recent studies in the rat (Guillery, 1956; Nauta, 1956) have confirmed much earlier descriptions of widespread distributions of the fornix system to the diencephalon and the rostral mid-brain regions. Besides the well-known massive hippocampal projections to the septal region (Ganser, 1882) and the mammillary body (Gudden, 1881), fornix components have been traced from the hippocampus to the preoptic region and the hypothalamus (Cajal, 1911), to the anterior nuclear complex and rostral intralaminar nuclei of the thalamus (Gudden, 1881; Vogt, 1898; Cajal, 1911), and to the rostral part of the central grey mid-brain substance (Edinger and Wallenberg, 1902).

941 citations

Journal ArticleDOI
01 Dec 1960-Brain
TL;DR: In the same year in which Gowers wrote the prophetic statement quoted above, Bechterew on the basis of mylogenetic studies described two ascending fibre systems in the anterolateral funiculus of the spinal cord, two systems that were directly continuous into the reticular formation of the brain-stem.
Abstract: In the same year in which Gowers wrote the prophetic statement quoted above, Bechterew on the basis of mylogenetic studies described two ascending fibre systems in the anterolateral funiculus of the spinal cord, two systems that were directly continuous into the reticular formation of the brain-stem. These two pathways consisted of a medial “ground bundle” of the lateral funiculus and a more lateral system of “the rest of the lateral funiculus,” exclusive of the dorsal spinocerebellar tract of Flechsig (text-fig. 1).

671 citations