Journal ArticleDOI
Efferent connections of the periaqueductal gray matter in the cat.
TLDR
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.read more
Citations
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Journal ArticleDOI
Cytoarchitectural subdivisions of the periaqueductal gray matter in the cat
TL;DR: The neuronal population of the PAG consists of relatively small cells, ranging from approximately 8 μ to 30 μ in diameter, of three different types and are classified as I, II, and III for the sake of convenience, distinguishable by differing neuronal distributions as well as by cellular characteristics.
Journal ArticleDOI
Morphine injected into the habenula and dorsal posteromedial thalamus produces analgesia in the formalin test
S. Robin Cohen,Ronald Melzack +1 more
TL;DR: Microinjection of morphine into the area of the habenula and dorsal posteromedial thalamus produces analgesia for tonic pain as measured by the formalin test in the rat, which is fully developed by the first time of testing, and is completely reversible by naloxone, an opiate antagonist.
Journal ArticleDOI
Somatosensory evoked responses in the mesencephalic central gray matter of the rat.
TL;DR: Short latency evoked potentials were recorded from central gray of the rat under deep Nembutal anesthesia to stimulation of any limb, the tail, or the face to find an intermediate degree of somatotopic organization.
Book ChapterDOI
Interconnectedness of Steroid Hormone-Binding Neurons: Existence and Implications
S. L. Cottingham,D. Pfaff +1 more
TL;DR: Neurons in the central nervous system concentrate estrogen, progesterone, testosterone or dihydrotestosterone, and corticosterone; in general, these neurons are found in brain regions that participate in behavioral and pituitary reproductive functions.
Journal ArticleDOI
Subcortical projections to the centromedian and parafascicular thalamic nuclei in the cat
TL;DR: The primary objective of this study is to identify the totality of input to the centromedian and parafascicular (CM‐Pf) thalamic nuclear complex.
References
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Two methods for selective silver impregnation of degenerating axons and their synaptic endings in the central nervous system.
Robert P. Fink,Lennart Heimer +1 more
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.
Book
The brain stem of the cat : a cytoarchitectonic atlas with stereotaxic coordinates
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.
Journal ArticleDOI
Hippocampal projections and related neural pathways to the mid-brain in the cat
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.
Journal ArticleDOI
Ascending axon degeneration following anterolateral cordotomy. An experimental study in the monkey.
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.