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1.
1.  An extracellular recording and staining technique has been used to study the structure of individual ventral-cord elements in the auditory pathway ofLocusta migratoria.
2.  Three groups of auditory ventral-cord neurons can be distinguished: (a) neurons ascending to the supraesophageal ganglion, (b) T-shaped neurons, and (c) neurons limited to the thoracic ventral cord.
3.  The ventral-cord neurons ascending to the supraesophageal ganglion link the auditory centers of the thorax to those of the supraesophageal ganglion. These are, at least in part, richly arborized neurons of large diameter.
4.  The ventral-cord neurons with T structure send equivalent signals along both arms of the T; they resemble the neurons of the first group in that they make synaptic connections in the supraesophageal ganglion, but they also conduct auditory information to caudal regions of the thorax via the descending trunk of the axon.
5.  In the supraesophageal ganglion there are several extensive projection areas of the auditory ventral-cord neurons. No direct connections to the mushroom bodies, the central body or the protocerebral bridge could be demonstrated.
6.  The thoracic ventral-cord neurons act as short segmental interneurons, providing a connection between the tympanal receptor fibers and the ascending and T-shaped ventral-cord neurons. They play a crucial role in auditory information processing.
7.  The possible functional properties of the various morphological sections of the auditory ventral-cord neurons are discussed, with reference to their connections with motor and other neuronal systems.
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2.
1.  The effects of potassium channel blockade on afferent axons and terminal regions in frog dorsal roots and spinal cords, respectively, were investigatedin vitro.
2.  A condition-test (C-T) protocol was used to assess the population relative refractory period. Characteristics of main axons were evaluated by stimulation at the proximal end of transected dorsal roots (DR). Characteristics of terminal regions were tested by stimulation at the base of the dorsal horn (DH).
3.  DH recovery of excitability was delayed by low concentrations of 4-aminopyridine (4-AP) and tetraethylammonium (TEA) alone or combined. The same treatments did not affect recovery to DR stimulation.
4.  DH recovery of excitability was not delayed by solutions suppressing terminal calcium influx.
5.  We conclude that sensitivity of the relative refractory period to potassium channel blocking agents differs between main axons and axon terminal regions. This may indicate differences between axon terminals and main axons in the mechanism of action potential repolarization.
6.  We hypothesize that rapid action potential repolarization by pharmacologically sensitive potassium channels in presynaptic terminal regions keeps terminal action potentials short. Terminal action potential brevity would limit calcium influx, thus preventing terminal calcium overload but contributing to transmission failures at spinal synapses.
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3.
1.  Inhibitory postsynaptic potentials (ipsps) produced by two classes of interneurons, CC (contralateral and caudal projecting) and lateral interneurons, were tested for strychnine sensitivity using paired intracellular recordings in the lamprey spinal cord. The ipsps were partially blocked by 0.2–0.5 M strychnine and were completely blocked by 5 M strychnine. Thus, the ipsps may be glycinergic.
2.  These interneurons are key participants in a proposed circuit model for fictive swimming. A connectionisttype computer simulation of the model demonstrated that the cycle period of the network increased with decreasing ipsp strength.
3.  Application of strychnine (0.1–0.5 M) to the spinal cord during fictive swimming induced by an excitatory amino acid increased cycle period, consistent with previous reports, but at odds with stimulation predictions.
4.  Strychnine also produced slow rhythmic modulation of fictive swimming (period = 12 s) which maintained left-right alternation and rostral-caudal coordination. Auto- and cross-correlation analyses revealed that the slow modulation was present in a weaker form in most control preparations during fictive swimming.
5.  Since the proposed model for the swimming pattern generator in the lamprey spinal cord does not predict the observed speeding with strychnine, nor the slow modulatory rhythm, it appears to be deficient in its present formulation.
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4.
1.  In the tortoise the capability of the spinal cord of generating rhythmic motor activity and of modulating reflex transmission depending on the motor cycle was investigated.
2.  In the intact animal co-ordinated locomotion was only observed if the feet had ground contact. Without ground contact only rhythmic struggling movements occurred. After spinalization some peripheral input was needed to initiate and sustain struggling movements in the air; the pattern of the movements was changed but not the frequency. After paralyzation the capability of generating a rhythmic activity was distinctly depressed in the spinal tortoise. The frequency of a rhythmic activity which could be induced in such a preparation by peripheral stimulation was very low, even after premedication with nialamide and DOPA.
3.  In the spinal paralyzed preparation during rhythmic motor activity a modulation of the membrane potential of motoneurones occurred with phases of depolarization and hyperpolarization. The latter at least partly were due to synaptic inhibition.
4.  In the spinal paralyzed preparation the transmission in excitatory reflex pathways from peripheral flexor reflex afferents (FRA) to motoneurones was phasically modulated during rhythmic motor activity in the way that the transmission was facilitated during the active phase of a motoneurone pool and inhibited during the reciprocal phase. In the inhibitory FRA pathways partly a particular kind of modulation of the transmission during the different phases was observed.
5.  The results indicate that the rhythmic motor activity in the spinal paralyzed tortoise which largely matched the activity found in cats, resembles in some aspects locomotor activity and therefore by analogy with findings in cats and turtles may be denoted as fictive locomotion.
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5.
In response female pheromone the male gypsy moth flies a zigzagging path upwind to locate the source of odor. He determines wind direction visually. To learn more about the mechanism underlying this behavior, we studied descending interneurons with dye-filled micro-electrodes. We studied the interneuronal responses to combinations of pheromone and visual stimuli.
1.  We recorded 5 neurons whose directionally selective visual responses to wide field pattern movement were amplified by pheromone (Figs. 2–6).
2.  The activity of the above neurons was more closely correlated with the position of the moving pattern than with its velocity (Fig. 4).
3.  One neuron showed no clearly directional visual response and no response to pheromone. Yet in the presence of pheromone it showed directionally selective visual responses (Fig. 6).
4.  We recorded 4 neurons whose directionally selective visual responses were not modulated by pheromone (Fig. 7), ruling out the possibility that the effect of the pheromone was simply to raise the activity of all visual neurons.
5.  Our results suggest that female pheromone amplifies some neural pathways mediating male optomotor responses, especially the directionally selective responses to the transverse movement of the image, both below and above the animal.
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6.
1.  Most Purkinje neurons show ongoing spike activity. In approximately 75%, this activity disappeared after peduncle lesion and in some of these the activity stopped when water flow over the gills was interrupted. Approximately one-fourth of Purkinje cells (PC's) showed continuing ongoing activity after afferent input was abolished.
2.  Stimulation of spinal cord elicited both simple spikes, mainly in ipsilateral PC's, and some complex responses (via climbing fibers) usually contralateral and of longer latency than the simple spikes.
3.  Tactile stimulation of skin and flexion of tail or fins, also lateral line stimulation by a water stream, evoked bursts of spikes in PC-s. Input was by mossy fibers and mechanoreceptive fields were large.
4.  Stimulation of vestibular nerve produced both simple and complex responses in PC's. Auditory stimuli were most effective at 800–1200 Hz in eliciting responses via mossy fibers. Responses to sound were phasic changes in ongoing frequency, bursts followed by inhibition or on-off excitation.
5.  Responses to visual stimuli were recorded in granule cells and Purkinje cells, also in mossy axons. Many PC's showed excitatory-inhibitory sequences; a few climbing fiber responses were recorded. The mossy fiber visual input is from optic tectum relay.
6.  Some PC's were activated by two or three sensory modalities.
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7.
Stinging behavior has been extensively studied in honey bees at the level of the individual, that is, in terms of stimuli that release stinging in adult bees, and in terms of integration of individual behavior into colony defense. Yet very little is known about the physiological basis for this behavior. Using an isolated abdominal preparation factors that influence peripheral control of the sting extension response are analyzed. Results show that:
1.  Electromyogram activity released by severing the ventral nerve cord changed during the first few days of adult life but not later. Abdomens from older bees (nurses, guards, foragers) showed significantly higher EMG activity than newly emerged or 24 h-old bees.
2.  The reflex matured over 5–7 days after emergence as an adult.
3.  Younger bees (24h) had a lower threshold for initiating sting extension than older bees. However, the threshold for initiating the full sting response, i.e., extension and venom pumping, did not differ due to age.
4.  Caste status was not correlated to any of the parameters of sting extension, indicating that any effect of caste on stinging behavior must arise in more anterior ganglia and/or in the brain.
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8.
1.  We have described a general ribonucleotide probein situ hybridization methodology for localization of mRNA in frozen, unfixed tissue sections of brain.
2.  The most important steps in obtaining consistent and reproducible autoradiographs with ribonucleotide probes were tissue acetylation and application of the radiolabeled probe to tissue sections under unsealed, glass coverslips.
3.  Variability of the hybridization signal in tissue sections has been minimized to achieve a high degree of reproducibility within a given experiment as determined by densitometric analysis of rat glucocorticoid and mineralocorticoid receptor mRNA hybridization autoradiographs.
4.  Tissue quality has been optimized for high-resolution anatomical localization of mRNA species by nuclear track emulsion.
5.  The protocol is amenable to rapid, batchwise processing of tissue samples.
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9.
Oncostatin M, a multifunctional cytokine   总被引：6，自引：0，他引：6  
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10.
1.  Auditory stimuli consisting of tape-recorded natural sounds were used in a study of 129 neurons in Field L of the caudal neostriatum in the forebrain of curarized starlings (Sturnus vulgaris).
2.  An extensive program of stimuli comprising many different signals (109 sound elements) was devised in order to permit identification of even very highly specialized neurons.
3.  As a rule, the time courses of the neuronal responses parallel those of certain parameters or parameter combinations of the sound stimuli. The responses of a few very specialized neurons, however, did not reflect any distinguishable temporal substructure within the effective sounds.
4.  64 neuons were examined with respect to the number of stimuli, out of a sample of 80 sound elements, eliciting a response. 24 of these neurons responded to less than 10 of the 80 natural sounds. These include neurons responding only to a single sound or to sounds of a single type.
5.  30 of the 64 neurons responded most strongly, or exclusively, to sounds of a single type.
6.  The criterion determining whether a neuron responds to a given sound may be a single parameter, a combination of parameters, or the entire complex of parameters describing the sound.
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11.
1.  In the polychaetePlatynereis dumerilii, the hormone-elaborating portion of the prostomium was determined by means of prostomium transection and implantation experiments. The area in question lies between the two pairs of eyes, extending longitudinally from the posterior border of the anterior eyes to about the posterior border of the posterior eyes. This corresponds approximately with the brain area delimited by the anterior and posterior dorsoventral connective tissue tubes and which is covered ventrally by the infracerebral gland epithelium.
2.  The infracerebral gland-complex and neurosecretory neurons within the brain were envisaged as possible sites of hormone synthesis.
3.  The infracerebral gland-complex inPl. dumerilii was investigated with light—and electron-microscopical techniques. A leaf-shaped area (measuring 120 by 95 m at the most) of the pericapsular epithelium at the ventral side of the brain, adjacent to the main blood vessel and to its efferent branches, consists of specialized columnar epithelial cells. Numerousa-cells and scarceb-cells can be distinguished. Fibre tracts with glia fibres and axons (some being neurosecretory axons) descend from the neuropile and in part terminate with prominent end-structures at the inner face of the brain capsule in the gland region. Probably some axons penetrate the capsule and make contact with the gland cells. Neither structural nor experimental findings prove that the infracerebral gland synthesizes the brain hormone. Accessory functions are discussed.
4.  Investigations in secretory brain cells ofPl. dumerilii are reported. In agreement with Müller (1973), a lack of correlation between the number of stainable neurosecretory neurons and the hormonal activity of the brain was found: in immature worms (to which high hormonal titers are ascribed) only few or even no neurosecretory brain cells at all were detectable. Prostomium transection and implantation experiments show further that not all regions of the brain which enclose neurosecretory neurons produce brain hormone. The results are discussed with reference to the hypotheses of Müller (1973) which suggest that the appearance of stainable neurosecretory brain cells indicates inactivation of neurons possibly previously involved with hormone synthesis.
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12.
1.  The reactions of tympanic nerve fibers ofLocusta migratoria were recorded by glass microelectrodes in the metathoracic ganglion.
2.  The units were classified by frequency-, intensity-, and directional characteristics as well as by their response pattern. The response to speciesspecific song is compared with the response to song ofEphippiger ephippiger.
3.  The physiological properties lead to a classification into three types of low-frequency neurons (characteristic frequency 3.5–4 kHz; 4kHz; 5.5–6 kHz) and one type of high-frequency neuron (12–20 kHz). This is similar to other species (Gray, 1960, Michelsen, 1971).
4.  Intensity-coding is done by sharp rising intensity characteristics and by different absolute thresholds of the units.
5.  There is a marked directional sensitivity with some differences between LF and HF units. In the low frequency range the tympanal organ seems to react as a pressure gradient receiver; for high frequencies another mechanism is discussed.
6.  No filtering of species-specific song takes place at the level of the receptor cells.
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13.
1.  The effects of the biogenic amines serotonin and octopamine on motion-sensitive neurons in the lobula of the honey bee were analysed electrophysiologically. Single cell activity was recorded intracellularly during application of amines. Field potentials in the lobula were recorded to measure the effects on populations of motion-sensitive neurons.
2.  Serotonin and octopamine modulate the response properties of motion-sensitive neurons in the lobula in a functionally antagonistic way.
3.  The application of serotonin, in most cases, reduces background activity as well as responses to moving stripe patterns by motion-sensitive lobula neurons. The direction specificity can also decrease after serotonin application. In accordance with the single cell recordings, the amplitudes of lobula field potentials evoked by moving stripe patterns are also reduced by application of serotonin.
4.  Octopamine leads to an increase in the amplitude and the initial slope of field potentials evoked by moving stripe patterns. However, there were no uniform effects at the single cell level after octopamine application.
5.  The modulatory effects of serotonin and octopamine on motion-sensitive neurons correlate well with some behavioral modifications elicited by these substances (Erber et al. 1991; Erber and Kloppenburg, companion paper).
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14.
Twelve of the main European LCA software packages currently available are examined wirh the aim of establishing which are the most appropriate for LCAs on industrial processes. The packages performances are assessed in terms of
–  • Volume of Data
–  • WindowsTM environment
–  • Network Capabilities
–  • Impact Assessment
–  • Graphical representation of the inventory results
–  • Sensitivity analysis
–  • Units
–  • Cost
–  • User Support
–  • Flow Diagrams
–  • Burdens allocation
–  • Transparency of data
–  • Input & output parameters
–  • Demo version
–  • Quality of data
The review concludes with a Specification Table which summarises the facilities available on each software package. The general conclusion from this study is that for industrially based LCAs, there are four packages which may offer advantages over the rest. These are The Boustead Model, The Ecobilan Group’s TEAM™, PEMS 3.0 and SimaPro 3.1.  相似文献   

15.
J. Robb 《Human Evolution》1994,9(3):215-229
In recent years anthropologists have made much progress in understanding ancient activities from skeletal remains. In this paper, material from the Iron Age cemetery at Pontecagnano (VII-IV century BC) is used to illustrate activity-related traits of eight basic categories:
(1)  idiosyncratic patterns of dental wear
(2)  activity-related articular degeneration
(3)  non-pathological functional alterations (neoformations, contact facets)
(4)  mechanical remodelling of bone architecture
(5)  enthesopathies (muscular lesions)
(6)  traumatic lesions
(7)  activity-related pathologies
(8)  activity-related nutritional characteristics
These traits, and others, can be used not only singly but in conjunction to define (a) patterns of activity and occupational specialization for individuals, and (b) distributions within society reflecting the basic division of labor by geneder and class.  相似文献   

16.
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17.
1.  The physiology and morphology of olfactory interneurons in the brain of larval Manduca sexta were studied using intracellular recording and staining techniques. Antennal olfactory receptors were stimulated with volatile substances from plants and with pure odorants. Neurons responding to the stimuli were investigated further to reveal their response specificities, dose-response characteristics, and morphology.
2.  We found no evidence of specific labeled-lines among the odor-responsive interneurons, as none responded exclusively to one plant odor or pure odorant; most olfactory interneurons were broadly tuned in their response spectra. This finding is consistent with an across-fiber pattern of odor coding.
3.  Mechanosensory and olfactory information are integrated at early stages of central processing, appearing in the responses of some local interneurons restricted to the primary olfactory nucleus in the brain, the larval antennal center (LAC).
4.  The responses of LAC projection neurons and higher-order protocerebral interneurons to a given odor were more consistent than the responses of LAC local interneurons.
5.  The LAC appears to be functionally subdivided, as both local and projection neurons had arborizations in specific parts of the LAC, but none had dendrites throughout the LAC.
6.  The mushroom bodies and the lateral protocerebrum contain neurons that respond to olfactory stimulation.
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18.
Müller  D. G.  Frenzer  K. 《Hydrobiologia》1993,(1):37-44
Culture studies with healthy and virus-infected isolates of Ectocarpus siliculosus, Feldmannia simplex and F. irregularis gave the following results:
–  Virus particles are produced in deformed reproductive organs (sporangia or gametangia) of the hosts and are released into the surrounding seawater.
–  Their infective potential is lost after several days of storage under laboratory conditions.
–  New infections occur when gametes or spores of the host get in contact with virus particles. The virus genome enters all cells of the developing new plant via mitosis.
–  Virus expression is variable, and in many cases the viability of the host is not impaired. Infected host plants may be partly fertile and pass the infection to their daughter plants.
–  Meiosis of the host can eliminate the virus genome and generate healthy progeny.
–  The genome of the Ectocarpus virus consists of dsDNA. Meiotic segregation patterns suggest an intimate association between virus genome and host chromosomes.
–  An extra-generic host range has been demonstrated for the Ectocarpus virus.
–  Field observations suggest that virus infections in ectocarpalean algae occur on all coasts of the world, and many or all Ectocarpus and Feldmannia populations are subject to contact with virus genomes.
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19.
1.  Coordinated movements of the wings during flight in the locust result from coordinated activity of flight neurons in the thoracic ganglia. Many flight interneurons and motoneurons fire synchronous bursts of action potentials during the expression of the flight motor pattern. The mechanisms which underlie this synchronous firing were investigated in a deafferented preparation of Locusta migratoria.
2.  Simultaneous intracellular recordings were taken from flight neurons in the mesothoracic ganglion using glass microelectrodes filled with fluorescent dye.
3.  Three levels of synchronous activity between synergistic motoneurons and between the right and left partners of bilaterally symmetrical pairs of interneurons were observed: bursting which was loosely in phase but which showed little correlation between the temporal parameters of individual bursts in the two neurons; bursting which showed synchrony of the beginning and end of bursts; and bursts which showed highly synchronous spike-for-spike activity.
4.  Direct interactions between the neurons had little or no part to play in maintaining any of the levels of synchrony, even in instances of very close synchrony (spikes in different neurons occurring within 1 ms of each other). Highly synchronous firing was a consequence of common synaptic input impinging on neurons with similar morphological and physiological properties.
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20.
1.  A 28-kDa peptide from the brain of the tobacco hornworm,Manduca sexta, was purifiedvia HPLC. The peptide copurified with the insect neurohormone, prothoracicotropic hormone (PTTH), through two HPLC columns.
2.  Immunocyctochemistry using polyclonal antibodies against the 28-kDa peptide revealed that the peptide was produced in the same protocerebral neurons that produce PTTH. Western blot analysis demonstrated that the 28-kDa peptide and big PTTH are different molecules.
3.  A PTTHin vitro bioassay indicated that despite having chromatographic properties similar to those of big PTTH and being produced by the same neurons, the 28-kDa peptide did not have PTTH activity.
4.  Amino acid sequence analysis yielded a 27 N-terminal amino acid sequence that had no similarity with known peptides.
5.  Immunocytochemical studies revealed that the 28-kDa peptide is present as early as 30% embryonic development and is absent by adult eclosion. This is in contrast to big PTTH, which is expressed throughout theManduca life cycle.
6.  These data suggest that the 28-kDa peptide is another secretory phenotype of the lateral neurosecretory cell group III (L-NSC III) which may have functions distinct from those for big PTTH or may act synergistically with big PTTH.
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