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1.
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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2.
1.  To determine the specificity of the goldfish (Carassius auratus) olfactory system to the reproductive pheromone 17,20-dihydroxy-4-pregnen-3-one (17,20P), and to determine if related sex steroids might also function as pheromones, electro-olfactogram (EOG) responses were recorded from mature male goldfish.
2.  Of the 24 steroids tested, 17,20P was the most stimulatory. It had a detection threshold of 10–12 M and at a concentration of 10–8 M elicited an EOG response 3 times that elicited by 10–5 M L-serine
3.  17,20,21-triol-4-pregnen-3-one, a metabolite of 17,20P, was the only other highly stimulatory steroid. Its threshold was 10–11 M.
4.  In cross-adaptation experiments EOG responses to all 21-carbon steroids were inhibited during adaptation to 17,20P: responses to this pheromone are transduced by a single receptor/transduction mechanism.
5.  To verify the biological relevance of EOG recording whole animal responsiveness was determined by measuring blood gonadotropin. When goldfish were placed into homogeneous steroid solutions endocrine responsiveness strongly correlated with EOG recording. However, when steroids were added to aquaria containing fish, responses were less specific indicating that transient wisps of steroids trigger endocrine responses.
6.  Although the extreme sensitivity and specificity of the goldfish olfactory system to 17,20P gives it the potential to serve as a highly specific cue, realization of this potential is probably determined by the dynamics of pheromone exposure.
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3.
Over 1500 root-nodule bacteria were isolated from a range of uninoculated soybeans, and one cowpea, trap-hosts, sown in 1985 into traditional soybean-growing areas of soybean-growing areas of northern Thailand. Most isolates were slow-growing Bradyrhizobium japonicum. Using a modified bottle-jar technique, 586 of the isolates were tested with a range of soybean hosts and one cowpea host. The results indicated:
(a)  a very high level of infectiveness, with only one isolate failing to nodulate one host, and 95% forming \s>20 nodules per plant;
(b)  a high level of effectiveness of fixation of nitrogen by the local rhizobium populations with soybeans;
(c)  evidence of selection of effective strains by both soybean and cowpea hosts in the field;
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4.
1.  When Xenopus laevis embryos swim into an obstruction they usually stop. This stopping response to stimulation on the head is present from stage 28 to 45. At stage 37/38 it is more reliable in restrained than in free-swimming animals, and to stimuli to the cement gland than to the head skin. Fictive swimming also stops reliably after the same stimuli but struggling and fictive struggling do not.
2.  Discharge of deformation-sensitive trigeminal sensory neurons in response to pressure on the cement gland or head skin precedes the fictive stopping response. When the embryo hangs from cement gland mucus, trigeminal neurons are active and the embryo is less responsive to stimulation.
3.  Lesions of the central nervous system have allowed us to draw the following conclusions about this inhibitory pathway: (a) either the cement gland or the head skin must be intact; (b) one trigeminal ganglion is both sufficient and necessary; (c) the pathway is independent of the forebrain and midbrain; (d) it can take an ipsilateral or contralateral route through the hindbrain; (e) at least two hindbrain interneuron components are involved.
4.  A similar stopping response is present in embryos and larvae of the urodele Ambystoma mexicanum.
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5.
The angular distribution of the optical axes of the ommatidia in the eyes of waterstriders (Gerris lacustris) has been investigated using antidromic illumination.
1.  Each eye contains about 920 ommatidia arranged in approximately 40 nearly horizontal rows (Figs. 5, 6).
2.  There is an acute zone (visual streak) of ±5° around the eye equator with high vertical resolution (Fig. 9).
3.  The horizontal interommatidial angle oh varies little with altitude and is in the frontal parts of the eye equal to the (horizontal) interrhabdomere angle rh (Fig. 10).
4.  Above and below the visual streak the eye is adapted to the perception of relative height or depth constancy (Fig. 13).
5.  Reconstruction of the viewing directions of the rhabdomeres in the visual streak reveals that characteristic groups of rhabdomeres in different ommatidia coincide in their receptive fields. Optical prerequisites for two types of neural superposition can be found: one of medium neural summation but highest sampling frequency, the other of highest neural summation at the cost of resolution (Fig. 11).
6.  The correspondence of the limits of resolution due to diffraction and finite sampling frequency is discussed.
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6.
With the aim of clarifying the role of screening pigments in photoreceptor optics of the compound eye, a comparative study of the optical properties of the honeybee eye in the visible region of the spectrum was carried out using wild-type bees and eye colour mutantssnow, snow laranja, ivoryumberandchartreuse with total or partial blockage of the tryptophane-ommochrome pathway.
1.  The electroretinogram (ERG) of mutant eyes displayed a sharp on-peak, this component being absent from normal heterozygote eyes (Fig. 6).
2.  The ERG of newly emerged bees (a) lacked the above on-peak and showed oscillations in mutants, and (b) lacked the off-peak which always occurs in the ERG of adults in all the genotypes studied when stimulated by visible light.
3.  The resting potentials of the receptor and cone cells were not found to be affected by mutations la, and the receptor potential ins/s ands la/slaphotoreceptors appeared to be similar to that in +/+
4.  Analysis of the amplitude characteristics of the whole eye of eight genotypes showed that the relative numbers of photons absorbed from an extended light source (4.5°×16.5°) and needed to elicit a standard ERG amplitude of 1 mV were as follows:s/si u/iusla/slach1/ch1(+/+; s/+ iu/+; sla/+)=14.38.612.2(100–250). These ratios are believed to reflect the progress in ommochrome formation in these strains.
5.  Spectral sensitivity curves (SSC) were obtained using an automatic spectrosensitometer and a spectral scan method which gave accurate results. The SSC of the whole eye in+/+ peaked at a max of 543±7 nm (SD,n=6), whereas max ins/s ands la/slashifted to 528±6 nm (n=9) and 548 ±3nm (n=6) respectively. The SSC ins/+ was the same as that in+/+. The bandwidth (width at 50% of peak sensitivity) of the SSC proved to be similar in+/+ ands/+ (126±10 nm and 128±8 nm), although ins/s the SSC appeared to be significantly narrower (106±7 nm;P<0.01; fig.=" 8,=" table=" 2).=">
6.  The peak spectral sensitivity of long-wave (LW) receptors lay at 541±5 nm (SD,n=14) in+/+ and at 526±5 nm (n=13) ins/s; the spectral distributions of the peaks in these genotypes were different. The bandwidth of the SSCs of the photoreceptors were 109±11 nm in+/+ and 103±4 nm ins/s, the difference being insignificant (Fig. 8, Table 2). The SSCs ins/s fit the absorption spectrum of pigment 526 (P 526) rather well whereas those in+/+ are noticeably distorted. The same is true for the whole-eye data.
7.  A theory is advanced to account for the acceptance functions of the photoreceptors of eyes with imperfect pigmentation. Light scattering in imperfectly screened eyes was estimated using a factor which the termed we parasitic absorption coefficientp (see Theory).
8.  The acceptance functions of LW photoreceptors were measured by three methods, and the results were similar to those predicted from the theory. On this basis the coefficientp was estimated; fors/s photoreceptors it lay between 0.65 and 0.76 according to experiments with a point light source (method 1), and was as great as 2.5 according to measurements with an extended light source (method 2). The latter technique, an integral method, made it possible to detect light scattering in normal bee eye, the coefficientp reaching 0.02 (Fig. 1, Table 3).
9.  In genotypes+/+ ands la/slathe absorption spectra of screening pigments were recorded by microspectrophotometry (MSP), and greater transmission of red light than blue-green was found (Fig. 11).
10.  Taking into account the screening effect of ommochromes, it is suggested that the visual pigment of LW photoreceptors in the honeybee eye is P 526; the absorption spectrum of this is highly similar to the SSC of LW photoreceptors in thes/s eye.
11.  On the basis of our theory and experimental results, the contrast transfer function (CTF) for the white honeybee eye was estimated to be only 0.1 (for white and black patterns with the spatial wavelength sp, the acceptance angle). Thus, the absence of screening pigments from the compound eye ofsnow mutants causes the great decrease in image contrast, and this serious sensory defect may be responsible for the fact that these mutants fail to find their way home.
Dedicated to Professor H. Autrum on the occasion of his 80th birthday  相似文献   

7.
The rich deciduous woodland at Loi, Luster, Inner Sogn, 61° 20 N., was traditionally used for fodder production from both tree and field layer. After more than nearly 40 years of disuse and secondary forest succession, experimental efforts were made to restore the traditional agricultural meadow woodland. Following a detailed preliminary registration of the vegetation the following measures were taken:
1.  The understory tree layer, mainly Alnus incana was removed.
2.  The old Ulmus glabra pollards were pruned back to traditional shape, as were some tall shurbs of Corylus avellana.
3.  The field layer was mown once or twice yearly.
The main results are:
1.  The pollarded elms have developed bundles of new twigs at the pruning points and are in good condition.
2.  After an expansion of tall, nitrophilic herbs, e.g. Urtica dioica, Impatiens noli-tangere and Rubus idaeus, low and medium sized herbs and grasses have increased both in numbers, frequency and abundance. Helio- and thermophilic forest margin species are also more prominent. The moss layer has also become more dense and varied.
3.  The average number of species in permanent plots has nearly doubled.
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8.
1.  The neurons of the pyloric network of the lobster (Panulirus interruptus) stomatogastric ganglion organize their rhythmic motor output using both chemical and electrical synapses. The 6 electrical synapses within this network help set the firing phases of the pyloric neurons during each rhythmic cycle. We examined the modulatory effects of the amines dopamine (DA), serotonin (5HT) and octopamine (Oct) on coupling at all the electrical synapses of the pyloric network.
2.  Electrical coupling within the pacemaker group [anterior burster (AB) to pyloric dilator (PD), and PD-
3.  Dopamine decreased or increased the coupling strength of all the pyloric electrical synapses: the sign of the effect depended upon which neuron was the target of current injection. For example, DA decreased AB PD coupling (i.e., when current was injected into the AB) but increased coupling in the other direction, PD AB. Dopamine decreased AB to VD coupling when current was injected into either neuron. Serotonin also had mixed effects; it enhanced PDAB coupling but decreased AB to VD and PD to VD coupling in both directions. Octopamine's only effect was to reduce PD VD coupling. li]4.
5.  The characteristic modulation of electrical coupling by each amine may contribute to the unique motor pattern that DA, 5HT and Oct each elicit from the pyloric motor network.
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9.
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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10.
1.  By penetrating axons in the ventral nerve cord of the dragonfly, Aeshna umbrosa, we measured the intracellular responses of target-selective visual interneurons to movement of black square targets ranging from 1° to 32° visual angle at several levels of mean background luminance.
2.  Neuronal responses, measured both in number of spikes and in the magnitude of integrated postsynaptic potentials, showed a preference for larger target size at lower mean luminance (Table 1, Figs. 1–3). The latency of postsynaptic potential (psp) and spike responses from onset of target movement increased with a decrease in mean luminance (Fig. 1).
3.  A measure of mean target size preference (Eqn. 1) for one identified interneuron (MDT4) in both laboratory and outdoor lighting shows a continuous decrease of preferred size with increases of mean luminance over more than 4 orders of magnitude.
4.  The time to reach the new steady state of cell response after the decrease of mean luminance was ordinarily less than 30 s, but sometimes longer (Fig. 4).
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11.
1.  Spectral-sensitivity functions of large-field movement-detecting units in the lobula plate of the dronefly Eristalis tenax L., which is a Batesian mimic of the honeybee, were measured using visual stimuli consisting of light flashes, or moving gratings. Two classes of units were studied, one class responding to inward horizontal motion in the contralateral eye (presumably the homologue of the well-known HI in other fly species), and the other class responding to vertically-down-ward motion in the contralateral eye.
2.  In both classes of units, the spectral-sensitivity function of the response to flashes is characterized by two peaks, one in the UV at ca. 350 nm and the other in the blue at ca. 475 nm (Figs. 3, 8). It resembles the spectral-sensitivity function of the R1-R6 class of receptors in other flies.
3.  In both classes of units, the spectral-sensitivity function of the response to movement is characterized by a single peak, occurring in the blue at ca. 450 nm (Figs. 7, 9).
4.  Control experiments on homologous units in the Australian Sheep Blowfly Lucilia cuprina, using identical stimulating conditions reveal that the response to flashes as well as movement possesses a dual-peaked spectral sensitivity, with one peak in the UV and the other in the blue-green region of the spectrum (Figs. 10–12).
5.  The results indicate that the pathways subserving the inputs to movement-detecting neurons in Eristalis are driven by more than one spectral class of photoreceptors. They also reveal that the spectral sensitivity of movement detection in Eristalis bears a closer resemblance to that of the honeybee, than to that of other flies. This similarity to the honeybee may arise from the fact that the dronefly and the honeybee occupy similar ecological niches, both foraging for nectar in flowers.
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12.
1.  The plating efficiency of bacteriophage MX-1 on Myxococcus xanthus strains A and B and M. virescens V2 were compared. Comparison of strains V2 and A suggest that V2 is restrictive and A is not (restriction coefficient was approximately 8). A derivative of M. virescens V2 (strain V2-9) was obtained by repeated exposure of strain V2 to ultraviolet radiation. Strain V2-9 was also unrestrictive. Strain B is apparently unrestrictive too but analysis of phenotypic changes in phage derived from hosts V2, B and A suggested that some of the host-cell processes differ from orthodox restriction and modification.
2.  Cell-free extracts from M. virescens V2 were fractionated by ion-exchange chromatography and two restriction endonucleases, R. MviV2I and R. MviV2II were identified. Nuclease I was found to hydrolyse coliphage DNA at apparently one site only and MX-1 DNA at approximately 10 sites; nuclease II was found to hydrolyse MX-1 DNA at a very large number of sites and its restriction sequence was of comparable frequency with that of R. EcoRII. Modified MX-1 DNA, obtained from phage whose last host was M. virescens V2 was hydrolysed by nuclease II but not by nuclease I. The significance of these findings for restriction in myxococci is discussed.
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13.
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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14.
1.  Chronic ingestion of caffeine by male NIH strain mice alters the density of a variety of central receptors.
2.  The density of cortical A1 adenosine receptors is increased by 20%, while the density of striatal A2A adenosine receptors is unaltered.
3.  The densities of cortical 1 and cerebellar 2 adrenergic receptors are reduced byca. 25%, while the densities of cortical 1 and 2 adrenergic receptors are not significantly altered. Densities of striatal D1 and D2 dopaminergic receptors are unaltered. The densities of cortical 5 HT1 and 5 HT2 serotonergic receptors are increased by 26–30%. Densities of cortical muscarinic and nicotinic receptors are increased by 40–50%. The density of cortical benzodiazepine-binding sites associated with GABAA receptors is increased by 65%, and the affinity appears slightly decreased. The density of cortical MK-801 sites associated with NMDA-glutaminergic receptors appear unaltered.
4.  The density of cortical nitrendipine-binding sites associated with calcium channels is increased by 18%.
5.  The results indicate that chronic ingestion of caffeine equivalent to about 100 mg/kg/day in mice causes a wide range of biochemical alterations in the central nervous system.
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15.
1.  The neuroantibody approach, based on the expression of selected monoclonal antibodies by cells of the nervous system, has recently been described (Cattaneo and Neuberger, 1987; Piccioliet al., 1991). In order to apply this experimental strategy to study the role of nerve growth factor (NGF) in the central nervous system (CNS), we exploited the monoclonal antibody (mAb),D11, which neutralizes very efficiently the biological activity of NGF, bothin vitro andin vivo (Cattaneoet al., 1988).
2.  TheD11 antibody chains were cloned and expressed in COS cells as rat/human chimaeric proteins. The cloned antibody was shown to display all the properties of the parentalD11 antibody, including its ability to neutralize NGF biological activity.
3.  This will allow us to engineer the expression of recombinantD11 antibodies in the CNS, to study the role of NGF in the developing and adult nervous system. This approach can be extended to other neurotrophic factors for which neutralizing monoclonal antibodies are available.
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16.
1.  Morphological correlates of circadian changes in eye sensitivity to light measured electrophysiologically were sought in the cockroach, Leucophaea maderae. Cross sections of ommatidia removed at subjective midday and subjective midnight on 3 successive days from roaches held under constant darkness (DD) at 25 ± 2 °C were examined using a transmission electron microscope for morphological differences related to sampling time.
2.  The temporal difference in submicrovillar cisternae (SMC) area appeared to exhibit a circadian rhythm, however, the amplitude of this temporal difference measured under DD was less than that observed under LD 1212 conditions. SMC areas characteristic at nighttime were achieved at subjective midnights but the area diminished only partially toward the daytime state on subjective middays.
3.  Rhabdom area remained constant and the daily rhythm of screening pigment granules (SPG) arrangement about the rhabdom was not observed under conditions of constant darkness.
4.  Results of this study indicate that a pacemaker(s) actively influences the change in the SMC toward the nighttime state, whereas, the change toward the daytime state results from a passive mechanism that possibly could be accelerated by light.
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17.
1.  The effects of three barbiturates and the local anesthetic procaine on the ion channel function of mouse nicotinic acetylcholine receptor (nAChR) muscle subtype expressed inXenopus laevis oocytes were examined by whole-cell voltage-clamp technique.
2.  A concentration-response curve for the specific nicotinic agonist dimethylphenylpiperazinium iodide (DMPP) was first determined. This agonist produced increasing whole-cell currents up to a concentration of 100µM (EC50 = 13µM), then decreased responses at higher concentrations.
3.  The barbiturates (amobarbital, secobarbital, pentobarbital) and procaine produced reversible inhibition of DMPP-induced currents at clinically used concentrations. The two classes of drugs differed in the voltage dependence of the inhibition: procaine-induced inhibition was increased at more negative transmembrane holding potentials (-90 vs. -45 mV); whereas amobarbital-induced inhibition did not vary at different transmembrane potentials.
4.  Mutant forms of the nAChR, containing single amino acid changes in the M2 regions of and subunits, showed increased sensitivity to procaine but no change in sensitivity to amobarbital-induced inhibition.
5.  These electrophysiologic studies provide further evidence that barbiturates and local anesthetics produce inhibition of the nAChR at different sites.
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18.
1.  The effects of the odorant compounds adenosine-5-monophosphate (5AMP), ammonium, betaine, L-cysteine, L-glutamate, DL-succinate, and taurine and of mixtures of these comounds on binding of taurine and 5AMP to dendritic membrane from the olfactory organ of spiny lobsters (Panulirus argus) were quantified to evaluate the contribution of inhibition of odorant-receptor binding to the generation of physiological responses to mixtures.
2.  Taurine binding sites belong to two affinity classes, while 5AMP binding sites belong to a single affinity class. Binding of either taurine or 5AMP was partially inhibited in an apparently noncompetitive, concentration dependent fashion by most odorant compounds, with 25–40 % inhibition by 1 mM of odorant. Mixtures of two or more odorant compounds also inhibited binding of taurine or 5AMP to its sites. However, the inhibition by mixtures was often significantly less than expected from the inhibition produced by a mixture's components assuming either a noncompetitive or competitive mechanism.
3.  By including this binding inhibition between compounds into models for predicting physiological responses to mixtures from the responses to the components, the predictive power of the models is significantly improved. This result strongly suggests that binding inhibition can influence the physiological responsiveness of chemoreceptor cells to mixtures.
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19.
Comparing the properties of young and senescent (aged) O+ erythrocytes isolated by applying ultracentrifugation in a self-forming Percoll gradient, we demonstrate that the sialic acids of membrane glycoconjugates control the life span of erythrocytes and that the desialylation of glycans is responsible for the clearance of the aged erythrocytes. This capture is mediated by a -galactolectin present in the membrane of macrophages. The evidence supporting these conclusions is as follows:
(1)  Analysis by flow cytofluorimetry of the binding of fluorescein isothiocyanate labelled lectins specific for sialic acids shows that the aged erythrocytes bind less WGA, LPA, SNA and MAA than young erythrocytes. The binding of DSA and LCA is not modified. On the contrary, the number of binding sites of UEA-I specific for O antigen and of AAA decreases significantly. PNA and GNA do not bind to erythrocytes.
(2)  RCA120 as well asErythrina cristagalli andErythrina corallodendron lectins specific for terminal -galactose residues lead to unexpected and unexplained results with a decrease in the number of lectin binding sites associated with increasing desialylation.
(3)  The glycoconjugates from the old erythrocytes incorporate more sialic acid than the young cells. This observation results from the determination of the rate of transfer by -2,6-sialyltransferase of fluorescent or radioactiveN-acetylneuraminic acid, using as donors CMP-9-fluoresceinyl-NeuAc and CMP-[14C]-NeuAc, respectively.
(4)  Microscopy shows that the old erythrocytes are captured preferentially by the macrophages relative to the young ones. Fixation of erythrocytes by the macrophage membrane is inhibited by lactose, thus demonstrating the involvement of a terminal -galactose specific macrophage lectin.
(5)  Comparative study of the binding of WGA, LPA, SNA and MAA to the aged erythrocytes and to thein vitro enzymatically desialylated erythrocytes shows that the desialylation rate of aged cells is low but sufficient to lead to their capture by the macrophages
These results were presented at the Jacques Monod Conference on Glycoconjugates (La Londe-les-Maures, 25–29 April 1994) and at the International Conference Romania and Romanians in Contemporary Science (Sinaia, 24–27 May 1994).  相似文献   

20.
1.  Honey bees (Apis mellifera, worker) were trained to discriminate between two random gratings oriented perpendicularly to each other. This task was quickly learned with vertical, horizontal, and oblique gratings. After being trained on perpendicularly-oriented random gratings, bees could discriminate between other perpendicularly-oriented patterns (black bars, white bars, thin lines, edges, spatial sinusoids, broken bars) as well.
2.  Several tests indicate that the stimuli were not discriminated on the basis of a literal image (eidetic template), but, rather, on the basis of orientation as a single parameter. An attempt to train bees to discriminate between two different random gratings oriented in the same direction was not successful, also indicating that the bees were not able to form a template of random gratings.
3.  Preliminary experiments with oriented Kanizsa rectangles (analogue of Kanizsa triangle) suggest that edge detection in the bee may involve mechanisms similar to those that lead to the percept of illusory contours in humans.
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