Pitch discrimination in locusts

1961 ◽  
Vol 155 (959) ◽  
pp. 218-231 ◽  
Keyword(s):  
Schistocerca Gregaria ◽  
Locusta Migratoria ◽  
Pitch Discrimination ◽  
High Pitch ◽  
Sound Stimulation ◽  
Sensory Axons ◽  
Metathoracic Ganglion ◽  
Tympanic Organ ◽  
The Brain ◽  
Stimulation Of

Sound stimulation of the tympanic organ of Locusta migratoria and Schistocerca gregaria initiates responses in the tympanic nerve and these in turn stimulate a few interneurones which ascend the ventral cord from the metathoracic ganglion to the brain. Some of the preparations show the following evidence of pitch discrimination. The response of the whole tympanic nerve to a pulsed note of low pitch cannot be made identical to the response to the same pulse at high pitch no matter how the relative inten­sities are adjusted. A continuous note, which presumably adapts some but not all of the primary receptors, modifies the relation between pre- and post-ganglionic responses in a way which depends on the pitch of the continuous note. The relative intensities of a pure tone of high pitch (10 to 15 kc/s) and one of low pitch (0.5 to 2.0 kc/s) can, in a preparation showing only ‘on' responses, be adjusted so that there is a post-ganglionic response to the former but not to the latter, although the latter causes a larger response in the tympanic nerve. Certain large interneurones, identifiable by their spike height, do not have the same curve of threshold to pulses of various pitch as does the summed response from the whole tympanic nerve. The post-ganglionic response is, therefore, towards a selected fraction of the sensory axons. In each of the above tests the effects are small and pitch discrimination cannot be of great significance for the life of the animal.

A guide to the neuroanatomy of locust suboesophageal and thoracic ganglia

1982 ◽  
Vol 297 (1085) ◽  
pp. 91-123 ◽  
Keyword(s):  
Peripheral Nerve ◽  
Nerve Fibre ◽  
Schistocerca Gregaria ◽  
Locusta Migratoria ◽  
Suboesophageal Ganglion ◽  
Thoracic Ganglia ◽  
Locusta Migratoria Migratorioides ◽  
Basic Framework ◽  
Metathoracic Ganglion ◽  
The Brain

The organization of the thoracic and suboesophageal ganglia in the locust is presented to provide a framework into which details of individual neurons can be inserted as information becomes available. Three species were examined, Chortoicetes terminifera (Walker), Schistocerca gregaria (Forskål) and Locusta migratoria migratorioides (Reiche and Fairmaire). The basic plan of the ganglia is similar in all three species. Series of selected sections in transverse, horizontal and sagittal planes are illustrated to show the arrangement of the main nerve fibre tracts and areas of neuropil, and these are described briefly. A guide is given to prominent features that assist in the interpretation of sections in each plane. In the simpler mesothoracic and prothoracic ganglia nine longitudinal tracts are present in each half of the neuromere, and six dorsal and four ventral transverse tracts (commissures) link the two halves. Four vertical or oblique tracts are conspicuous, the T-tract, ring tract, C-tract and I-tract. Major roots of each peripheral nerve useful as landmarks are numbered from anterior to posterior. Two regions of fine fibrous neuropil are prominent, the ventral association centre and an area associated with the ring tract, a little above it. In the metathoracic ganglion three abdominal neuromeres are fused posteriorly to the true metathoracic neuromere. All four neuromeres show modification of the basic framework chiefly in the arrangement of the ventral commissures and the degree of development of the ventral association centre. In the suboesophageal ganglion three neuromeres, mandibular, maxillary and labial, are fused together from anterior to posterior. They show increasing modification of the basic plan anteriorly. Additional anterior longitudinal tracts are present, which connect with the brain, the dorsal commissures are much reduced and compressed, particularly in the mandibular neuromere, and the ventral commissures of all three neuromeres differ considerably from those of the thoracic ganglia.

scholarly journals Connections of Hindwing Tegulae with Flight Neurones in the Locust, Locusta Migratoria

1988 ◽  
Vol 135 (1) ◽  
pp. 381-409 ◽  
Author(s):  
K. G. PEARSON ◽  
H. WOLF
Keyword(s):  
Electrical Stimulation ◽  
Schistocerca Gregaria ◽  
Locusta Migratoria ◽  
Postsynaptic Potentials ◽  
Major Function ◽  
Metathoracic Ganglion ◽  
Tethered Flight ◽  
Discharge Patterns ◽  
Spike Initiation ◽  
Stimulation Of

1. The connections of afferents from the hindwing tegulae to flight motoneurones and interneurones in the locust, Locusta migratoria, have been determined by selectively stimulating the tegula afferents while recording intracellularly from identified neurones in the meso- and metathoracic ganglia. 2. Electrical stimulation of the hindwing tegula nerve (nerve lCla) revealed two groups of afferents distinguished by a difference in their conduction velocities. Both groups of afferents made excitatory connections to hindwing elevator motoneurones in the ipsilateral half of the metathoracic ganglion. Latency measurements indicated that these connections were monosynaptic. Stimulation of the hindwing tegula nerve also evoked excitatory postsynaptic potentials (EPSPs) in elevator motoneurones in the mesothoracic ganglion and in the contralateral half of the metathoracic ganglion, and inhibitory postsynaptic potentials (IPSPs) in forewing and hindwing depressor motoneurones. The latencies of these evoked EPSPs and IPSPs indicated that the initial responses were produced via interneuronal pathways. 3. None of the recordings revealed EPSPs in depressor motoneurones or IPSPs in elevator motoneurones in response to hindwing tegula stimulation. This observation differs from that in Schistocerca gregaria where it has been reported that the large tegula afferents produce EPSPs in depressors and IPSPs in elevators (Kien & Altman, 1979). 4. Some of the interneurones in disynaptic excitatory and inhibitory pathways to motoneurones were identified. These interneurones received input from both hindwing tegulae and were readily excited beyond threshold by mechanical stimulation of the tegulae or by electrical stimulation of the tegula afferents. The contribution of one excitatory interneurone to the electrically evoked EPSPs was assessed by blocking spike initiation in the interneurone while recording simultaneously from a flight motoneurone. 5. Based on our observations of the central connections of tegula afferents to flight motoneurones and the previously reported discharge patterns of these afferents during tethered flight (Neumann, 1985), we propose that a major function of the hindwing tegulae in L. migratoria is to generate the initial depolarizations in forewing and hindwing elevator motoneurones during flight. Consistent with this proposal was our finding that ablation of the hindwing tegulae delayed the onset of elevator activity relative to the onset of the preceding depressor activity.

Central Mechanism of Hearing in Insects

1961 ◽  
Vol 38 (3) ◽  
pp. 545-558 ◽  
Author(s):  
NOBUO SUGA ◽  
YASUJI KATSUKI
Keyword(s):  
Sound Source ◽  
Threshold Curve ◽  
Inhibitory Interaction ◽  
Response Range ◽  
Metathoracic Ganglion ◽  
Hair Sensilla ◽  
Prothoracic Ganglion ◽  
Tympanic Organ ◽  
Large Fibre ◽  
The Brain

1. The impulses from the tympanic organ are transmitted at the prothoracic ganglion to a central neuron, the auditory T large fibre, which lies in the cord between the brain and the metathoracic ganglion. The impulses in the T large fibre are conducted rostrally and caudally with the same discharge pattern. Information is sent up to the brain, and down to the metathoracic ganglion, after a delay of about 12 msec. 2. The impulses from the cercal hair sensilla are transmitted to two similar auditory C large fibres which lie in the cord between the metathoracic and last (6th) abdominal ganglia and are then sent up to the mesothoracic ganglia by other auditory large fibres. 3. Central inhibitory interaction between the impulses from the tympanic nerves of the two sides are shown by a marked increase of impulses in the T large fibre following section of one of the tympanic nerves. No inhibitory interaction is found between the impulses from the two cercal nerves. 4. The auditory T large fibre receives not only the excitatory effect from the ipsilateral tympanic nerve at the prothoracic ganglion, but also the inhibitory and weak excitatory effects from the contralateral one. 5. The response range of the T large fibre is narrower than the threshold curve of the tympanic nerve and corresponds with one type of response range in the tympanic neurons. The response ranges of the C large fibres correspond closely with the threshold curve of the cercal nerve. 6. A large difference in threshold between the two T large fibres is found in the response to sound incident from the side. The number of impulses in the T large fibre nearer to the sound source is greater than in that farther from the source. 7. The difference in the number of impulses between the two T large fibres is most marked in the response to sound of the frequency which is dominant in stridulation. This difference is due to the mutual inhibitory interaction of neurons which modifies the number of impulses without changing the threshold of the tympanic large fibre. 8. It is suggested that the central inhibitory interaction increases the information about a sound source and plays an important role in the mechanism of the directional sense. 9. The stridulation of the group activates the tympanic nerve and evokes synchronized discharge in the T large fibre, but scarcely at all in the primary C large fibre. The tympanic organ and its neural network seem well adapted to reception of stridulation. 10. It is concluded that though neither of the two sound receptive organs--the tympanic organ and the cercal hair sensilla--can perform frequency analysis, the insect may be able to do so by making use of both organs, since they have different frequency ranges and are served by different auditory large-fibre tracts.

The Control of Changes in Peripheral Sensilla Associated with Feeding in Locusta Migratoria (L.)

1972 ◽  
Vol 57 (3) ◽  
pp. 755-763
Author(s):  
E. A. BERNAYS ◽  
R. F. CHAPMAN
Keyword(s):  
Normal Level ◽  
Electrical Resistance ◽  
Locusta Migratoria ◽  
Corpus Cardiacum ◽  
Corpora Cardiaca ◽  
Diuretic Hormone ◽  
Stretch Receptors ◽  
The Brain ◽  
Maxillary Palps ◽  
Stimulation Of

1. The electrical resistance across the tips of the maxillary palps is not affected by stimulation of the palps, but increases to the normal level found after feeding as a result of distension of the foregut with agar or injection of corpus cardiacum homogenates into the haemolymph. 2. No increase in resistance occurs if the posterior pharyngeal nerves or the frontal connectives are cut. 3. It is inferred that distension of the foregut stimulates stretch receptors which, acting via the posterior pharyngeal nerves, the frontal connectives and the brain, cause the release of hormone from the storage lobes of the corpora cardiaca. This hormone acts on the terminal sensilla of the palps, causing them to close and so increasing the resistance across the palps. 4. Release of the diuretic hormone is controlled via the same pathway.

THE MODULATORY EFFECT OF SCHISTOFLRFamide ON HEART AND SKELETAL MUSCLE IN THE LOCUST SCHISTOCERCA GREGARIA

1994 ◽  
Vol 197 (1) ◽  
pp. 437-442 ◽  
Author(s):  
S Robb ◽  
P Evans
Keyword(s):  
Skeletal Muscle ◽  
Nervous System ◽  
Synthetic Peptide ◽  
Schistocerca Gregaria ◽  
Locusta Migratoria ◽  
Visceral Muscles ◽  
Spontaneous Contractions ◽  
Dose Dependent ◽  
Dose Dependent Effect ◽  
Stimulation Of

SchistoFLRFamide (PDVDHVFLRFamide) is one of the endogenous FMRFamide-like neuropeptides found in the nervous system of the locust Schistocerca gregaria (Robb et al. 1989; Robb and Evans, 1990). FMRFamide-like neuropeptides modulate the actions of a wide variety of both skeletal and visceral muscles in insects (Evans and Myers, 1986a; Schoofs et al. 1993b) and have been suggested to act both as circulatory hormones and as locally released neurotransmitters (see discussion in Robb and Evans, 1990). However, the behavioural context(s) in which such neuropeptides are released is at present unclear, although recent evidence suggests they may have a role in feeding behaviour (Elia et al. 1993). SchistoFLRFamide belongs to one of the subclasses of FMRFamide-like neuropeptides found in insects, which also includes leucomyosuppressin (pQDVDHVFLRFamide; Holman et al. 1986), ManducaFLRFamide (pQDVVHSFLRFamide; Kingan et al. 1990) and TDVDHVFLRFamide found in both Drosophila melanogaster (Nichols, 1992) and Neobellieria bullata (Fonagy et al. 1992). The sequence of SchistoFLRFamide has also been found in Locusta migratoria (Schoofs et al. 1993a). SchistoFLRFamide was originally isolated from the nervous system of Schistocerca gregaria using a combination of radioimmunoassay, HPLC and bioassay (Robb et al. 1989; Robb and Evans, 1990). Preliminary data indicate that it inhibits spontaneous contractions of the locust heart and has a complex dose-dependent effect upon contractions induced in the extensor tibiae muscle by stimulation of the slow excitatory motoneurone (Robb et al. 1989). In addition, SchistoFLRFamide has recently been shown to decrease the amplitude and frequency of myogenic contractions and to reduce basal tension in locust oviduct muscle (Peeff et al. 1993). The present paper provides a more detailed account of the modulatory effect of SchistoFLRFamide on heart and skeletal muscle in the locust Schistocerca gregaria. The effects of the synthetic peptide were measured on the semi-isolated locust heart (Cuthbert and Evans, 1989). The results are expressed as the percentage change in the amplitude of the heartbeat and its frequency with respect to measurements obtained immediately before the application of the peptide. Measurements of heart rate and contraction amplitude were averaged over a 1 min period, starting (a) 1 min before the beginning of the peptide pulse, (b) 1 min after the start of the peptide pulse, (c) 4 min after the start of the peptide pulse and (d) 1 min after the end of the peptide pulse. The bioactivity of synthetic SchistoFLRFamide was also assayed on another well-defined FMRFamide bioassay preparation from the locust. The effects were measured on the twitch tension evoked in the extensor tibiae muscle of the hindleg of the locust by stimulating the slow excitatory motoneurone to this muscle at 1 Hz (Evans and Myers, 1986b). The results are expressed as the maximal effects on the twitch amplitude.

scholarly journals Evidence for the cholinergic markers ChAT and vAChT in sensory cells of the developing antennal nervous system of the desert locust Schistocerca gregaria

2020 ◽  
Vol 20 (4) ◽  
Author(s):  
Erica Ehrhardt ◽  
George Boyan
Keyword(s):  
Nervous System ◽  
Schistocerca Gregaria ◽  
Central Complex ◽  
Sensory Cells ◽  
Desert Locust ◽  
Cholinergic Transmission ◽  
Sensory Axons ◽  
First Instar ◽  
The Brain ◽  
Antennal Nerve

AbstractSensory and motor systems in insects with hemimetabolous development must be ready to mediate adaptive behavior directly on hatching from the egg. For the desert locust S. gregaria, cholinergic transmission from antennal sensillae to olfactory or mechanosensory centers in the brain requires that choline acetyltransferase (ChAT) and the vesicular acetylcholine transporter (vAChT) already be present in sensory cells in the first instar. In this study, we used immunolabeling to demonstrate that ChAT and vAChT are both expressed in sensory cells from identifiable sensilla types in the immature antennal nervous system. We observed ChAT expression in dendrites, neurites and somata of putative basiconic-type sensillae at the first instar stage. We also detected vAChT in the sensory axons of these sensillae in a major antennal nerve tract. We then examined whether evidence for cholinergic transmission is present during embryogenesis. Immunolabeling confirms that vAChT is expressed in somata typical of campaniform sensillae, as well as in small sensory cell clusters typically associated with either a large basiconic or coeloconic sensilla, at 99% of embryogenesis. The vAChT is also expressed in the somata of these sensilla types in multiple antennal regions at 90% of embryogenesis, but not at earlier (70%) embryonic stages. Neuromodulators are known to appear late in embryogenesis in neurons of the locust central complex, and the cholinergic system of the antenna may also only reach maturity shortly before hatching.

scholarly journals The Posture of the Abdomen during Locust Flight: Regulation by Steering and Ventilatory Interneurones

1990 ◽  
Vol 151 (1) ◽  
pp. 109-131 ◽  
Author(s):  
ANDREAS BAADER
Keyword(s):  
San Diego ◽  
Locusta Migratoria ◽  
Selective Inhibition ◽  
University Of California ◽  
Selective Stimulation ◽  
Metathoracic Ganglion ◽  
Behavioural Patterns ◽  
Flight Frequency ◽  
La Jolla ◽  
Stimulation Of

1. Tethered flying locusts (Locusta migratoria) make correctional steering movements with the abdomen when stimulated with a moving artificial horizon and integrated wind jet, simulating deviation from a straight course. 2. Neurones in the metathoracic and first abdominal neuromeres of the metathoracic ganglion have been characterized morphologically and physiologically. The selective stimulation of these cells causes movements of the abdomen. 3. One group of neurones responds directionally to visually perceived horizon movements and is excited by wind on the head. Some of these neurones are rhythmically activated at the flight frequency while others receive tonic drive from the flight oscillator. Electrical depolarization results in bending of the abdomen; the direction of this movement is always compatible with compensatory steering. 4. Interneurones which are active during the expiration phase of ventilation also contribute to the posture of the abdomen in flight. They are not visually responsive but their selective inhibition at the onset of flight activity helps to bring the abdomen into flight posture. Some of these interneurones are modulated at the flight frequency. 5. The efficiency of cooperation between different sets of interneurones inproducing behavioural patterns and the signficance of single neurone stimulation are discussed. Note: Present address and address for offprint requests: Department of Biology, B-002, University of California at San Diego, La Jolla, CA 92093, USA.

Hindleg targeting during scratching in the locust

1997 ◽  
Vol 200 (1) ◽  
pp. 93-100 ◽  
Author(s):  
T Matheson
Keyword(s):  
Tactile Stimulation ◽  
Schistocerca Gregaria ◽  
Sensory Information ◽  
Sensory Receptors ◽  
Mechanical Constraints ◽  
Metathoracic Ganglion ◽  
The Central Nervous System ◽  
Stimulus Site ◽  
Site Of Stimulation ◽  
Stimulation Of

Intact locusts (Schistocerca gregaria) respond to tactile stimulation of their folded wings with rhythmic scratching movements of the ipsilateral hindleg that are directed towards the site of stimulation. For example, sites near the base of a wing elicit anteriorly directed scratches, whereas sites near the distal end of a wing elicit posteriorly directed scratches. Locusts also scratch in response to tactile stimulation of a wing that is held outstretched in a posture similar to that normally adopted during flight, but they fail to alter their leg targeting to compensate for this changed position of the stimulus site. Instead, they scratch at an empty point in space near the abdomen, where the stimulus site would have been if the wing was folded in the resting posture. This inappropriate scratching does not result from mechanical constraints on the hindleg's movement, from stimulation of abdominal sensory receptors, or from an absence of sensory information from the outstretched wing. It also persists when the metathoracic ganglion that controls movements of the hindlegs is isolated from the remainder of the central nervous system (CNS). Targeted scratching of sites on the wings of locusts therefore appears to be fixed relative to body coordinates and does not take into account alterations of the target wing's position.

Synaptic activation of efferent neuromodulatory neurones in the locust Schistocerca gregaria

1998 ◽  
Vol 201 (24) ◽  
pp. 3339-3354 ◽  
Author(s):  
S. Baudoux ◽  
M. Burrows
Keyword(s):  
Schistocerca Gregaria ◽  
The Body ◽  
Strong Correlations ◽  
Nerve Roots ◽  
Dorsal Midline ◽  
Synaptic Potentials ◽  
Metathoracic Ganglion ◽  
Dorsal Unpaired Median ◽  
Different Parts ◽  
Stimulation Of

The segmental ganglia of the locust contain efferent neuromodulatory neurones with cell bodies at the dorsal midline and axons that supply muscles and other tissue on both sides of the body. These are the dorsal unpaired median (DUM) neurones. Intracellular recordings were made from pairs of known metathoracic efferent DUM neurones in locusts in which all nerves were intact and in isolated metathoracic ganglia. The 19 metathoracic, efferent DUM neurones were identified according to the nerve roots through which their axons emerge from the ganglion. The synaptic potentials in these DUM neurones have been analysed to investigate how these neurones are activated and how their spikes are controlled. The degree of correlation between the synaptic potentials in particular pairs of neurones was quantified using a correlation analysis. This allowed the population of DUM neurones to be divided into three subsets that also map onto an anatomical grouping based on the distribution of their axons in the lateral nerves: (i) DUM1 neurones (DUMDL and DUM1b); (ii) DUM3 and DUM3,4 neurones; and (iii) DUM3,4,5, DUM5b neurones and DUMETi. Individual neurones within each subset showed strong correlations between their synaptic potentials, in both intact locusts and isolated ganglia, and tended to spike at the same time. Neurones in different subsets had few synaptic potentials in common and tended to spike independently. The persistence of common synaptic potentials in neurones of the three subsets in isolated ganglia indicates that they are derived from neurones within the metathoracic ganglion. The DUM neurones that had many common synaptic potentials in a quiescent locust responded in similar ways to mechanosensory stimulation of different parts of the body. DUM3,4, 5 and DUM5 neurones gave the clearest and most consistent responses to stimulation of mechanoreceptors on either hind leg. DUM3 and DUM3, 4 neurones responded variably, but usually with a hyperpolarisation. DUM1 neurones were rarely excited by mechanosensory stimuli but, like the preceding group, their responses were dependent upon whether the locust was moving its legs. These results lend further support to the idea that there is a subdivision of action amongst this population of DUM neurones, with those supplying the same targets being driven by the same presynaptic local neurones.

Chemical Stimulation of the Brain Makes Stimulating Reading

1975 ◽  
Vol 20 (12) ◽  
pp. 923-924
Author(s):  
MADGE E. SCHEIBEL ◽  
ARNOLD B. SCHEIBEL
Keyword(s):  
Chemical Stimulation ◽  
The Brain ◽  
Stimulation Of
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