Location of efferent sympathetic neurons and afferent neurons in spinal ganglia innervating the heart

Location and numbers of neurons associated with sympathetic innervation of the heart within the right stellate and accessory cervical ganglia, the spinal cord, and spinal ganglia were investigated using horseradish peroxidase retrograde axonal transport techniques in cats. The enzyme was applied to central sections of the anastomosis of the stellate ganglion with the vagus nerve, the inferior cardiac nerve, and the vagosympathetic trunk caudal to the anastomosis. Labeled neurons within the stellate ganglion were located close to the point of departure of the nerves and more thinly distributed in the accessory cervical ganglion. A group of labeled cells was found in the anastomosis itself. Preganglionic neurons associated with sympathetic innervation of the heat were detected at segmental levels T₁–T₅ in the spinal cord. Labeled neurons were diffusely located in the spinal ganglia, concentrated mainly at levels T₂–T₄.Medical Institute, Ministry of Public Health of the RSFSR, Yaroslavl'. Translated from Neirofiziologiya, Vol. 21, No. 1, pp. 106–111, January–February, 1989.     

Some morphological and functional properties of the lateral line system of the dwarf catfish

The peripheral and central portions of the lateral line system of the dwarf catfish were studied by morphological and electrophysiological methods. The posterior lateral line nerve, innervating the electro- and mechanoreceptors of the trunk, was shown to consist of poorly myelinated fibers 2–9 µ in diameter. The conduction velocity in this nerve varied from 10 to 15 m/sec. The lateral line nerves end in the medial nucleus of the acoustico-lateral region, which consists of dorsal and medial parts. The former is composed of circular and triangular cells measuring 6–14 µ, the second part by circular cells measuring 4–6 µ. These parts of the medial nucleus are most sharply differentiated in the region of entry of the auditory nerve. Responses to stimulation of the lateral line electro- and mechanoreceptors were recorded over the whole of the acousticolateral region in the caudal-rostral direction. The neurons studied were located at depths of 400–800 µ in the region of the medial nucleus.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad, Translated from Neirofiziologiya, Vol. 7, No. 2, pp. 203–207, March–April, 1975.     

Projections from neurons of the medial terminal nucleus of the accessory optic tract to the caudate nucleus in the cat revealed by combining techniques of retrograde axonal transport and experimentally induced degeneration

Neurons of the medial terminal nucleus of the accessory optic tract receiving direct retinal inputs were shown to project to the heat and body of the caudate nucleus in the cat using techniques of retrograde horseradish peroxidase axonal transport and experimentally induced degeneration. These primarily ipsilateral projections are evenly distributed throughout the aforementioned areas of the nucleus. Neurons of the medial terminal nucleus forming synaptic connections with caudate nucleus cells are distinguished by their varied shapes and sizes, ranging from 20 × 10 to 37.5 × 18 µm and are located in both the ventral and dorsal subdivisions of the nucleus. The supposed functional significance of these projections for the regulation of muscle tonus tension is discussed.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 18, No. 2, pp. 214–219, March–April, 1986.     

Distribution of GABA-like immunoreactivity during post-metamorphic development and regeneration of the central nervous system in the ascidian Ciona intestinalis

During regeneration of the neural ganglion in Ciona intestinalis, the pattern of reappearance of some peptidergic cells is similar to the ontogenetic patterns exhibited by these cell types during normal post-metamorphic development. Using a specific antiserum to gamma-aminobutyric acid (GABA), we describe here the appearance of GABA-ergic cells in Ciona during both post-metamorphic development and regeneration of the neural ganglion following total ablation. Post-metamorphic animals were divided into the categories: 1, 3–5, 6–10, 11–15 and 23–27 mm in body length. Regeneration was monitored at 12, 15, 18, 21, 28 and 56 days post ablation. The first appearance of GABA-like immunoreactive cells during normal development were at the 3 to 5-mm stage where they were seen as discrete cells, without processes, evenly distributed in the cortical region throughout the ganglion. Fibres were first seen at the 6 to 10-mm stage. As development proceeded, GABA-like immunoreactive cells became more concentrated near the nerve root exits and along the dorsal rind of the ganglion. In regenerating ganglia, GABA was first detected at 18–21 days post ablation, in cells that lacked any obvious processes and that were distributed in all regions of the ganglion. At 28 days post ablation, processes could be detected in the neuropile, and after 56 days GABA cells were found predominantly in the same regions as in the normally developing adult ganglion. Although the overall pattern reflects that in a normal adult, a few differences were detectable. For example, rather more GABAergic cells were concentrated ventrally in the ganglion close to the neural gland.     

Similarities and differences in the structure of segmentally homologous neurons that control the hearts in the leech,Hirudo medicinalis

Summary The neural circuit that controls the hearts in the leech comprises an ensemble of synaptically interconnected cardiac motor neurons (HE cells) and cardiac interneurons (HN cells). Both the HE cells and the HN cells constitute segmentally homologous sets. We have investigated the structure of these neurons by iontophoretic injection of Lucifer Yellow dye.Bilateral pairs of HE cells have been identified in segmental ganglia 3–19 of the nerve cord. Their structure was found to be nearly identical from ganglion to ganglion and from animal to animal.Bilateral pairs of HN cells have been identified in segmental ganglia 1–7 of the nerve cord. Their dendritic structure was found to vary from ganglion to ganglion. These segmental differences among HN cells were observed consistently from animal to animal. Some of the segmental differences in HN cell structure correlate with previously described physiological differences.     

Structural asymmetry in the frog retinal ganglion cell layer

The density of distribution and topographical features of small and large ganglion cells were investigated in total silver-impregnated preparations of the retina from two species of frogs (Rana ridibunda andR. temporaria). A horizontal band of increased density of ganglion cells was located in both species above the nasotemporal axis passing through the blind spot. Outside this band the density of the small cell population was maximal in the central zone of the retina, decreasing toward the periphery. In the upper halves of the retina the density of small cells was on average 26% greater than in the lower halves. Large ganglion cells, on the other hand, were more densely distributed in the lower half of the retina than in the upper half; this difference was particularly marked inR. temporaria (by 116%). The large cells were asymmetrically distributed relative to the dorsoventral axis also: In the nasal quadrants their density was 40–55% greater than in the temporal. Large cells were more densely distributed in the middle zone of the retina. Signs of asymmetry in the organization of the retinal output raster may be of adaptive ecologic importance and may determine the characteristics of formation of visually controlled food and avoidance behavioral reflexes.Research Institute of Applied Mathematics and Cybernetics, N. I. Lobachevskii State University, Gorkii. Translated from Neirofiziologiya, Vol. 17, No. 2, pp. 198–204, March–April, 1985.     

Electron-microscopic analysis of adrenergic nerve endings in the cat caudal mesenteric ganglion

The ultrastructure of nerve endings of the cat caudal mesenteric ganglion was studied after fixation of the material with 4% lithium permanganate solution by Richardson's method in the modification of Hökfelt et al. [12]. This fixation method was shown to permit the demonstration of numerous adrenergic as well as cholinergic nerve endings. Four types of adrenergic organelles were distinguished in neurons of the ganglion: small and large granular vesicles 30–50 and 70–90 nm in diameter, respectively, a tubular reticulum with electron-dense contents, and small granular vesicles 15–20 nm in diameter. The localization of the adrenergic endings and their relations with other processes and cells of the caudal mesenteric ganglion were studied in detail. The problem of the origin and physiological role of adrenergic nerve endings in this ganglion is discussed.Institute of Physiology, Academy of Sciences of the Belorussian SSR, Minsk. Translated from Neirofiziologiya, Vol. 12, No. 1, pp. 86–92, January–February, 1980.     

Ultrastructure of interneuronal connections in the superior cervical sympathetic ganglion in cats

The structure of interneuronal synapses in the superior cervical sympathetic ganglion was studied in cats under normal conditions and after division of the cervical sympathetic nerves and removal of spinal ganglia T₁₂–L₂. A definite number of dendro-dendritic and dendro-somatic junctions is observed in the ganglion and most of them remained intact after operations of both types; they are probably synapses formed by dendrites of neurons located in the ganglion. Synapses of this sort participate in the formation of nest-like complexes, consisting of consecutive junctions of one neuron with several dendrites. The formation of such complexes may provide the anatomical basis for synchronization of rhythmic neuronal activity in the cellular glomeruli of the ganglion. The results of an ultrastructural study of dendro-dendritic junctions suggests that they are synaptic in nature. Some dendro-dendritic junctions underwent degeneration after both types of operation and are probably endings of neurons in spinal ganglia. Wide club-like structures, probably receptor endings, formed by dendrites of afferent neurons of spinal ganglia, also are found in the ganglion. These structures lie freely in the stoma of the ganglion or form contacts with axon terminals and dendrites of neurons located in the ganglion; some of them degenerate after removal of spinal ganglia T₁₂–L₂.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 13, No. 3, pp. 299–306, May–June, 1981.     

Neural control of heartbeat in the pteropod mollusk Clione limacina

The heart of the pteropod molluskClione limacina is innervated by the median nerve arising from the left abdominal ganglion. Five neurons sending axons to the heart have been identified in theClione central nervous system with retrograde cobalt or Lucifer yellow staining. Neuron H1 located in the left pedal ganglion produced an excitatory effect on heart beat. Stimulation of three neurons, H2–H4, situated in a compact group in the medial region of the left abdominal ganglion, led to inhibition of cardiac contraction, while H5, located in the caudal region of the left abdominal ganglion, did not affect heart beat. The activity of efferent cardiac neurons (ECN) was found to be related to the operation of the locomotor rhythm generator. Spontaneous or reflex depression of the latter was found to inhibit neuron H1 and activate units H2–H4. The behavior of these ECN accounts for the positive correlation between heart operation and locomotor activity inClione limacina.Institute of Research on Information Transmission, Academy of Sciences of the USSR, Moscow, M. V. Lomonosov State University, Moscow. Translated from Neirofiziologiya, Vol. 21, No. 2, pp. 185–192, March–April, 1989.     

Electrical activity of the sympathetic ganglia during the depressor reflex

Tonic activity of neurons of the superior cervical sympathetic ganglion was recorded by the "sucrose gap" method and in the 4th and 5th lumbar sympathetic ganglia with the aid of focal nonpolarizing electrodes in acute experiments on anesthetized cats and rabbits. The preganglionic fibers of the ganglia were left intact. Stimulation of the depressor nerve not only sharply inhibited the tonic activity of the ganglia but also led to the appearance of electropositive potentials of 0.7 ± 0.2 mV in the superior cervical ganglion and 20–250 µV in the lumbar ganglia. The amplitude of this potential was unchanged by atropine (1 · 10^–6M). A similar effect occured without stimulation of the depressor nerve, after division of the preganglionic fibers or blocking of their conduction; it is attributed to the cessation of preganglionic tonic impulses which induce not only spikes, but also many EPSPs in neurons of the ganglion. Their frequency in the lumbar ganglia was 4/sec. Summation of these EPSPs leads to constant electronegativity of the ganglion surface relative to the postganglionic fibers, and its disappearance is recorded as a positive potential. Stimulation of the depressor nerve thus does not induce IPSPs in the ganglion; consequently, the inhibition of synaptic activity observed under these circumstances is located in the CNS and not in the ganglion.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 6, No. 5, pp. 519–524, September–October, 1974.     

Electrophysiological investigation of the conduction of excitation in the pterygopalatine ganglion of the cat

When responses in some nerves of the pterygopalatine ganglion of the cat in situ to stimulation of its other nerves were recorded it was found that most fibers passing through the ganglion are continuous sympathetic postganglionic fibers (at least three groups). Most of the parasympathetic preganglionic fibers forming synapses on neurons of the ganglion constitute a group of fibers with the same threshold of excitation. Intracellular recording from single neurons of the pterygopalatine ganglion showed that stimulation of the Vidian nerve evokes orthodromic spike potentials in some neurons of the ganglion with a short latent period, and in others with a long latent period (2.5–6.0 and 10–44 msec, respectively). Evidently only fast-conducting fibers terminate synaptically on most neurons of the ganglion and only slow-conducting fibers on some of them. Recording from intact nerves of the pterygopalatine ganglion revealed no tonic activity in them. Microelectrode recording from single neurons of the ganglion showed that either the frequency of generation of spike potentials is relatively low (1–3/sec) or such potentials are absent altogether.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 8, No. 5, pp. 514–520, September–October, 1976.     

Neuronal responses of the reticular and anterior ventral thalamic nuclei to stimulation of the thalamic ventrolateral nucleus and motor cortex

Responses of 137 neurons of the rostral pole of the reticular and anterior ventral thalamic nuclei to electrical stimulation of the ventrolateral nucleus and motor cortex were studied in 17 cats immobilized with D-tubocurarine. The number of neurons responding antidromically to stimulation of the ventrolateral nucleus was 10.5% of all cells tested (latent period of response 0.7–3.0 msec), whereas to stimulation of the motor cortex it was 11.0% (latent period of response 0.4–4.0 msec). Neurons with a dividing axon, one branch of which terminated in the thalamic ventrolateral nuclei, the other in the motor cortex, were found. Orthodromic excitation was observed in 78.9% of neurons tested during stimulation of the ventrolateral nucleus and in 52.5% of neurons during stimulation of the motor cortex. Altogether 55.6% of cells responded to stimulation of the ventrolateral nucleus with a discharge of 3 to 20 action potentials with a frequency of 130–350 Hz. Similar discharges in response to stimulation of the motor cortex were observed in 30.5% of neurons tested. An inhibitory response was recorded in only 6.8% of cells. Convergence of influences from the thalamic ventrolateral nucleus and motor cortex was observed in 55.7% of neurons. The corticofugal influence of the motor cortex on responses arising in these cells to testing stimulation of the ventrolateral nucleus could be either inhibitory or facilitatory.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 10, No. 5, pp. 460–468, September–October, 1978.     

Single unit responses of the reticular and ventral anterior nuclei of the thalamus to electrical stimulation of the centrum medianum

In acute experiments on cats anesthetized with thiopental (30–40 mg/kg, intraperitoneally) and immobilized with D-tubocurarine (1 mg/kg) responses of 145 neurons of the reticular and 158 neurons of the ventral anterior nuclei of the thalamus to electrical stimulation of the centrum medianum were investigated. An antidromic action potential appeared after a latent period of 0.3–2.0 msec in 4.1% of cells of the reticular nucleus and 4.4% of neurons of the ventral anterior nucleus tested in response to stimulation. The conduction velocity of antidromic excitation along axons of these neurons was 1.7–7.6 m/sec. Neurons responding with an antidromic action potential to stimulation both of the centrum medianum and of other formations were discovered, electrophysiological evidence of the ramification of such an axon. Altogether 53.8% of neurons of the reticular nucleus and 46.9% of neurons of the ventral anterior nucleus responded to stimulation of the centrum medianum by orthodromic excitation. Among neurons excited orthodromically two groups of cells were distinguished: The first group generated a discharge consisting of 6–12 action potentials with a frequency of 130–640 Hz (the duration of discharge did not exceed 60 msec), whereas the second responded with a single action potential. Inhibitory responses were observed in only 0.7% of neurons of the reticular nucleus and 4.4% of the ventral anterior nucleus tested. Afferent influences from the relay nuclei of the thalamus, lateral posterior nucleus, and motor cortex were shown to converge on neurons responding to stimulation of the centrum medianum.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 12, No. 1, pp. 36–45, January–February, 1980.     

Substance P-like immunoreactive trigeminal ganglion cells supplying the cornea

Summary Trigeminal ganglion cells supplying the cornea were traced with intra-axonally transported horseradish peroxidase and, subsequently studied for the presence of substance P-like immunoreactivity. Approximately 0%–30% of trigeminal ganglion cells contained immunoreactive substance P. These cells were of a small size (15–50 m in diameter) and were distributed throughout the ganglion. The ganglion cells supplying the cornea were of a relatively small size as well but were confined to the anteromedial part of the ganglion. Some of these cells were found to contain immunoreactive substance P.     

Connections of the corticospinal and rubrospinal tracts with neurons of the cervical spinal cord in cats

The distribution of focal potentials over the cross section of the 7th cervical segment of the spinal cord was studied during stimulation of the pyramids, the red nucleus, and a peripheral nerve (ulnar) in adult cats anesthetized with chloralose and Nembutal. The earliest focal potentials in the fasciculus dorsolateralis were recorded 1.4–1.5 msec after stimulation of the pyramids and 0.8–0.9 msec after stimulation of the red nucleus. These times correspond to maximal condution velocities of 56–68 and 105–124 m/sec respectively. The earliest post-synaptic activity in response to pyramidal stimulation was found in the lateral areas of laminae V and VI, and in response to stimulation of the red nucleus in laminae VI and VII in Rexed's classification. The pyramidal wave also evoked considerable postsynaptic activity in medial areas of the dorsal horn. In response to stimulation of peripheral afferents activity was evoked in neurons in the central and medial parts of laminae V and VI. It is postulated on the basis of these results that corticospinal and rubrospinal fibers may be connected monosynaptically with specialized interneurons, free from peripheral influences, in the lateral areas of laminae V and VII respectively; in the lateral part of lamina VI convergence of both types of influences on the same cells is possible. Interaction between descending and afferent influences possibly takes place on more medially located neurons.A.A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 4, No. 2, pp. 158–167, March–April, 1972.     

Asymmetrical dendritic fields of retinal ganglion cells

By use of Golgi chrome—silver impregnation, studies were made of the dendritic branchings of feline and frog ganglion cells. It was shown that besides the known varieties of ganglion cells there were asymmetrical neurones whose dendrites lay all to one side. Essential differences distinguished these ganglion cells in the cat from those in the frog, differences depending upon the architectonics of the inner plexiform layer, which is broad and subdivided into layers in the frog, and narrow in the cat. We discuss the possible role of neurones with a unilateral arrangement of dendrites in relation to know electrophysiological data on retinal detectors and the receptive fields of ganglion cells.Brain Institute, Academy of Medical Sciences of the USSR, Moscow. Translated from Neirofiziologiya, Vol. 3, No. 3, pp. 301–307, May–June, 1971.     

Sources of thalamic afferents projecting to the suprasylvian gyrus of the black sea porpoise

Neurons sending fibers to different loci of the suprasylvian gyrus (SSG) of the porpoise(Phocaena phocaena) cortex were located in the thalamus by retrograde horseradish peroxidase transport and fluorescent tracing techniques. Horseradish peroxidase injection into the anterior section of the suprasylvian gyrus led to retrograde labelling of neurons in the lateral portion of the ventrobasal complex of nuclei and the ventroposteroinferior nucleus. A group of labelled cells was found in the ventral section of the main medial geniculate nucleus. Injecting bisbenzimide into different loci of the medial suprasylvian gyrus also led to retrograde labelling of neurons belonging to the ventral division of the main medial geniculate nucleus. Somewhat lower numbers of labelled cells were found in the inferior nucleus of the pulvinar. Small groups of labelled neurons were also found in the lateral nucleus of the pulvinar, the medioventral nucleus of the medial geniculate body, and the posterior complex of nuclei. A similar distribution of labelled cells was also observed after injecting bisbenzimide into the more caudal portion of the gyrus, although the location of labelled cells in the ventral division of the main medial geniculate nucleus and the lower pulvinar nucleus were shifted in a lateral direction.A. N. Severtsov Institute of Animal Evolutionary Moprhology and Ecology, Academy of Sciences of the USSR, Moscow. National University, Singapore. Translated from Neirofiziologiya, Vol. 21, No. 4, pp. 529–539, July–August, 1989.     

Effects of applying microelectrostimulation to different cell type zones in the caudate nucleus

The effects of applying electromicrostimulation to areas of the caudate nucleus with different neuronal activity patterns were investigated during chronic experiments on four cats. Caudate sites containing neurons responding to presentation of various sensory stimuli were selected for the first set of experiments and those where no neuronal activity manifested in the second series. Histological verification of electrolytic marker sites produced by electrical stimulation took place at the end of each experimental sequence and the cell types surrounding these lesions were examined. Microelectrostimulation consistently produced movement in the animal in the first set of experiments; markers were located along the surface of striosomes among large-sized cells, bundles of fibers, and blood vessels. In the second, electrical stimulation produced no alteration in naturally occurring animal behavior; markers were located within striosomes in accumulations of small- and medium-sized cells. A survey of the findings obtained would confirm our hypothesis that the neurons from which activity had been recorded by extracellular techniques in the caudate nucleus are large-sized cells with long axons.Institute for Research into Information Transmission, Academy of Sciences of the USSR, Moscow. Translated from Neirofiziologiya, Vol. 22, No. 2, pp. 162–171, March–April, 1990.     

A study of the cerebral region of the visual system in the pulmonata

The distribution of central axons of receptor cells of the eyes and the locations of neurons sending axons into the optic nerves were studied in the cerebral ganglia of the pulmonate mollusksLymnaea stagnalis andHelix sp. by the method of axonal transport of cobalt chloride injected via the optic nerves. Afferent fibers of these nerves form terminal ramifications (chiefly dorsally) in the middle part of the cerebral ganglion. Some of them pass through the commissure to the symmetrical region of the opposite cerebral ganglion. Neurons innervating the eyes are located in several regions of both cerebral ganglia. InLymnaea they are distributed near the point of entry of the optic nerve, in the region of the commissure, the mesocerebrum, and the posterior part of the ganglion. InHelix these neurons are found in the same regions except in the posterior part of the ganglion. In electrophysiological experiments responses of neurons in these parts of the cerebral ganglion to adequate stimulation of the eye were recorded. Differences in the character of responses and also the presence of neurons indifferent to stimulation of the eye are evidence of the functional heterogeneity of these areas. This suggests that morphologically separate visual centers do not exist in the cerebral ganglion of the Pulmonata. Neurons giving specific responses to stimulation of the eye and evidently belonging to different levels of the visual system (afferent or efferent divisions) are closely connected both with each other and with cells of other functional systems.A. A. Ukhtomskii Physiological Research Institute, A. A. Zhdanov Leningrad State University. Translated from Neirofiziologiya, Vol. 14, No. 2, pp. 179–184, March–April, 1982.     

Unit responses in area 5b of the suprasylvian gyrus to stimulation of the posterior lateral thalmamic nucleus

In response to stimulation of the posterior lateral nucleus in unanesthetized cats immobilized with D-tubocurarine an evoked potential consisting of three components with a latent period of 3–5 msec appeared in area 5b of the suprasylvian gyrus. All three components were reversed at about the same depth in the cortex (1500–1600 µ). Reversal of the potential shows that it is generated in that area by neurons evidently located in deeper layers of the cortex and is not conducted to it physically from other regions. Responses of 53 spontaneously active neurons in the same area of the cortex to stimulation of the posterior lateral nucleus were investigated. A characteristic feature of these reponses was that inhibition occurred nearly all of them. In 22 neurons the responses began with inhibition, which lasted from 30 to 400 msec. In 30 neurons inhibition appeared immediately after excitation while one neuron responded by excitation alone. The latent periods of the excitatory responses varied from 3 to 28 msec. The short latent period of the evoked potentials and of some single units responses (3–6 msec) confirms morphological evidence of direct connections between the posterior lateral nucleus and area 5b of the suprasylvian gyrus. Repetitive stimulation of that nucleus led to strengthening of both excitation and inhibition. Influences of the posterior lateral nucleus were opposite to those of the specific nuclei: the posterior ventrolateral nucleus and the lateral and medial geniculate bodies. Stimulation of the nonspecific reticular nucleus, however, evoked discharges from neurons like those produced by stimulation of the posterior lateral nucleus.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 5, No. 5, pp. 502–509, September–October, 1973.