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.

Contralateral coordination and retargeting of limb movements during scratching in the locust

1998 ◽  
Vol 201 (13) ◽  
pp. 2021-2032 ◽  
Author(s):  
T Matheson
Keyword(s):  
Nerve Cord ◽  
Tactile Stimulation ◽  
Schistocerca Gregaria ◽  
Limb Movements ◽  
Single Cycle ◽  
Experimental Conditions ◽  
The Subject ◽  
The Common ◽  
Peripheral Sensory ◽  
Stimulus Site

Locusts, Schistocerca gregaria, in common with many limbed vertebrates, can make directed scratching movements in response to tactile stimulation. For instance, stimulation of different sites on a wing elicits different movements that are accurately targeted so that the hindleg tarsus passes across the stimulus site. I have analysed these limb movements to define the ability of a locust to target stimulus sites correctly under a range of experimental conditions. In particular, I describe aspects of the behaviour that reveal possible neuronal pathways underlying the responses. These neuronal pathways will be the subject of further physiological analyses. Limb targeting during scratching is continuously graded in form; different patterns of movement are not separated by sharp transitions. The computation of limb trajectory takes into account the starting posture of the hindleg, so that different trajectories can be used to reach a common stimulus site from different starting postures. Moreover, the trajectories of the two hindlegs moving simultaneously from different starting postures in response to a single stimulus can be different, so that their tarsi converge onto the common stimulus site. Different trajectories can be used to reach a common stimulus site from the same start posture. Targeting information from a forewing is passed not only down the nerve cord to the ipsilateral hindleg but also across the nerve cord, so that the contralateral hindleg can also make directed movements. This contralateral transmission does not rely on peripheral sensory feedback. When the stimulus site moves during a rhythmical scratch, the targeting of subsequent cycles reflects this change. Both ipsilateral and contralateral hindlegs can retarget their movements. The trajectory of a single cycle of scratching directed towards a particular stimulus site can be modified after it has begun, so that the tarsus is redirected towards a new stimulus site.

Efferent neurons and suspected interneurons in S-1 vibrissa cortex of the awake rabbit: receptive fields and axonal properties

1989 ◽  
Vol 62 (1) ◽  
pp. 288-308 ◽  
Author(s):  
H. A. Swadlow
Keyword(s):  
Receptive Fields ◽  
Mean Value ◽  
Field Analysis ◽  
Layer 2 ◽  
Efferent Neurons ◽  
High Stimulus ◽  
The Central Nervous System ◽  
Frequency Burst ◽  
Stimulus Site ◽  
Stimulation Of

1. The behavioral tractability of the rabbit was exploited and enabled, in the fully awake state, receptive-field analysis of antidromically identified efferent neurons within the vibrissa representation of primary somatosensory cortex (S-1). Efferent neurons studied included ipsilateral corticocortical neurons (C-IC neurons, n = 56) that project to or beyond the second somatosensory cortical area (S-2) and corticofugal neurons of layer 5 (CF-5 neurons, n = 75) and layer 6 (CF-6 neurons, n = 92) that project to and/or beyond the thalamus. 2. An additional class of neurons was studied that was not activated antidromically from any stimulus site, but which responded synaptically to electrical stimulation of the ventrobasal (VB) thalamus with a burst of three or more spikes at frequencies of 600 to greater than 900 Hz. Most of these neurons also responded synaptically to stimulation of S-2. The action potentials of these neurons were much shorter (mean = 0.43 ms), than those of efferent neurons (mean = 0.98 ms). Such properties have been associated with interneurons found throughout the central nervous system, and these neurons are thereby referred to as suspected interneurons (SINs). Although SINs were found at all cortical depths, a strong peak in the distribution occurred just superficial to the peak in the distribution of CF-5 neurons. Most SINs located within this peak responded to deflection of only a single vibrissa. In contrast, SINs located in layer 6 and in layer 2-3 responded to deflection of many vibrissae (median = 11.0 and 5.5 vibrissae, respectively). In addition, SINs of layer 6 and layer 2-3 had significantly longer synaptic latencies to stimulation of VB thalamus than did SINs located at intermediate cortical depths. 3. The properties of efferent neurons and SINs differed considerably. Efferent neurons never responded to stimulation of VB thalamus with the high-frequency burst of spikes characteristic of SINs. Although greater than 70% of CF-6, CF-5 and C-IC neurons had receptive fields that were directionally selective, only 20% of SINs showed any degree of directional selectivity. Furthermore, SINs showed both much lower angular thresholds to vibrissa deflection and a much greater ability to follow high-stimulus frequencies than was seen in efferent neurons. The spontaneous firing rates of SINs had a mean value of 16.5 spikes/s, which was the highest seen in any population within S-1. 4. CF-5 neurons had a number of properties which contrasted with those of both CF-6 and C-IC neurons.(ABSTRACT TRUNCATED AT 400 WORDS)

Touch sensitivity in oligochaete giant fibers is transiently enhanced by a single spike

1996 ◽  
Vol 74 (5) ◽  
pp. 841-844
Author(s):  
David E. Turnbull ◽  
Charles D. Drewes
Keyword(s):  
Tactile Stimulation ◽  
Lumbriculus Variegatus ◽  
Giant Fiber ◽  
Non Invasive ◽  
Touch Sensitivity ◽  
Single Spike ◽  
Weak Stimulus ◽  
Site Of Stimulation ◽  
Stimulation Of ◽  
Touch Stimulus

Weak tactile stimulation of posterior segments in the freshwater oligochaete Lumbriculus variegatus evokes a single lateral giant fiber (LGF) spike but no overt escape shortening. After initiation of a single spike, giant-fiber excitability is increased, as reflected by a period of enhanced conduction velocity for a second LGF spike that follows 5–50 ms after the first. Using non-invasive recordings from intact worms and a biofeedback arrangement for stimulus delivery, it was shown that the period of enhanced velocity is associated with a marked increase in sensitivity to a second touch stimulus. Enhanced touch sensitivity is distributed within the LGF sensory field to loci remote from the original site of stimulation, leading to an increased likelihood that a second, weak stimulus will elicit rapid escape withdrawal.

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.

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.

scholarly journals Respiration in the Desert Locust

1960 ◽  
Vol 37 (2) ◽  
pp. 224-236 ◽  
Author(s):  
P. L. MILLER
Keyword(s):  
Carbon Dioxide ◽  
Central Nervous System ◽  
Nervous System ◽  
Schistocerca Gregaria ◽  
Thoracic Ganglion ◽  
Desert Locust ◽  
Maximum Volume ◽  
Metathoracic Ganglion ◽  
The Central Nervous System

1. Normal (dorso-ventral) and three auxiliary ventilating mechanisms (neck, prothoracic and abdominal longitudinal) are described in the non-flying Schistocerca gregaria. 2. Neck and prothoracic ventilation together contribute 14% of the maximum volume of air pumped by the insect. Head ganglion receptors must be stimulated for these forms to appear. 3. The metathoracic ganglion may contain a pacemaker controlling the frequency and amplitude of all forms of ventilation. Each head and thoracic ganglion contains carbon-dioxide receptors which modify the activity of the pacemaker. There is no control from the abdomen in the intact insect, or from receptors outside the central nervous system. 4. Oscilloscope recordings from the isolated central nervous system demonstrate a rhythm, which is modified and possibly initiated by carbon dioxide. 5. It is suggested that carbon dioxide normally provides a more important ventilatory stimulus than oxygen lack.

Electrophysiological correlates of tactile and visual perception during goal-directed movement

2012 ◽  
Vol 25 (0) ◽  
pp. 170
Author(s):  
Georgiana Juravle ◽  
Tobias Heed ◽  
Charles Spence ◽  
Brigitte Roeder
Keyword(s):  
Tactile Stimulation ◽  
Visual Stimulation ◽  
Visual Stimuli ◽  
Sensory Information ◽  
Event Related Potentials ◽  
Sensory Receptors ◽  
Directed Movement ◽  
Tactile Information ◽  
Execution Phase ◽  
Related Potentials

Tactile information arriving at our sensory receptors is differentially processed over the various temporal phases of goal-directed movements. By using event-related potentials (ERPs), we investigated the neuronal correlates of tactile information processing during movement. Participants performed goal-directed reaches for an object placed centrally on the table in front of them. Tactile and visual stimuli were presented in separate trials during the different phases of the movement (i.e., preparation, execution, and post-movement). These stimuli were independently delivered to either the moving or the resting hand. In a control condition, the participants only performed the movement, while omission (movement-only) ERPs were recorded. Participants were told to ignore the presence or absence of any sensory events and solely concentrate on the execution of the movement. The results highlighted enhanced ERPs between 80 and 200 ms after tactile stimulation, and between 100 and 250 ms after visual stimulation. These modulations were greatest over the execution phase of the goal-directed movement, they were effector-based (i.e., significantly more negative for stimuli presented at the moving hand), and modality-independent (i.e., similar ERP enhancements were observed for both tactile and visual stimuli). The enhanced processing of sensory information over the execution phase of the movement suggests that incoming sensory information may be used for a potential adjustment of the current motor plan. Moreover, these results indicate a tight interaction between attentional mechanisms and the sensorimotor system.

scholarly journals Reflex Effects of the Femoral Chordotonal Organ Upon Leg Motor Neurones of the Locust

1982 ◽  
Vol 101 (1) ◽  
pp. 265-285 ◽  
Author(s):  
L.H. FIELD ◽  
M. BURROWS
Keyword(s):  
Sense Organ ◽  
Attachment Site ◽  
Joint Effect ◽  
Chordotonal Organ ◽  
Function Generator ◽  
Metathoracic Ganglion ◽  
Motor Neurones ◽  
Direction Of Movement ◽  
The Central Nervous System ◽  
Stimulation Of

The femoral chordotonal organ (FCO) in a hind leg of a locust monitors the position and movement of the tibia about the femur. It consists of a group of sensory neurones embedded in connective tissue attached distally by two structures: the apodeme, which inserts close to the apodeme of the extensor tibiae muscle, and the flexor strand, which inserts at the base of the apodeme of the flexor tibiae muscle. The action of the apodeme and the flexor strand is reciprocal during movements of the tibia; the apodeme is stretched during flexion of the tibia whilst the flexor strand is relaxed. During extension, the apodeme is relaxed and the flexor strand is stretched. To analyse the reflex effects of this sense organ, all other sense organs of a hind leg were denervated. The apodeme of the FCO was then grasped between forceps, severed from its distal attachment site and its movements controlled by a function generator. The flexor strand remained intact and could be stimulated independently by moving the tibia. The different reflex effects mediated by the separate stimulation of the two components of the FCO were revealed by making intracellular recordings from the somata of leg motor neurones in the metathoracic ganglion. A movement stimulus to either component in a way that corresponded to tibial extension, excited flexor tibiae and inhibited extensor tibiae motor neurones. There was also an inter-joint effect whereby extension excited the depressor tarsi and inhibited the levator tarsi motor neurones. A flexion movement had the converse effects on these motor neurones. The effectiveness of the two components was dependent upon the velocity of the stimulus, the set position of the femoro-tibial joint at which the stimulus was applied, the initial direction of movement, and the activity of other neurones in the central nervous system. Slow motor neurones were depolarized more by low velocities of movement, whereas fast ones were depolarized more by high velocities. The two components produced their greatest effects at the set positions where they were most stretched; thus the apodeme was most effective when the joint was flexed, and the flexor strand when it was extended. Elicited movements of the hind legs or apparently spontaneous changes of excitability enhanced or masked the typical response of the motor neurones to stimulation of the FCO, indicating that the effects of this sense organ are not to be viewed as rigid, but as modifiable in the context of the behaviour of the animal. Note:

Control of the respiratory mode in air-breathing fishes

1988 ◽  
Vol 66 (1) ◽  
pp. 144-151 ◽  
Author(s):  
Neal J. Smatresk
Keyword(s):  
Sensory Information ◽  
Great Variability ◽  
Diverse Group ◽  
Sensory Receptors ◽  
Air Breathing ◽  
Aerial Respiration ◽  
Reflex Responses ◽  
Oxygen Sensitive ◽  
Respiratory Reflex ◽  
Stimulation Of

The transition from water breathing to air breathing for most bimodally breathing fishes appears to be critically dependent on sensory information from three major sets of peripheral receptors. Dominant control over the respiratory mode arises from stimulation of oxygen-sensitive chemoreceptors. Stimulation of internally oriented chemoreceptors generally increases both aquatic and aerial respiration, while stimulation of external chemoreceptors may shift the ventilatory emphasis from water to air breathing. Air-breathing organ mechanoreceptors may help to reflexively stimulate or inhibit air breathing upon deflation or inflation of the air-breathing organ, and probably play a major role in matching ventilation to perfusion in the air-breathing organ. Waterborne irritants or emersion stimulate defense receptors that may override control priorities set by other receptors, and inhibit branchial ventilation in favor of air breathing. While there is still little detailed information about the distribution and characteristics of these sensory receptors, it seems likely that similar sets of receptors control the respiratory mode in most air-breathing fishes, and that differences in the central integration of this sensory information may best account for the great variability of respiratory reflex responses in this diverse group of animals.

The Central Nervous Control of Flight in a Locust

1961 ◽  
Vol 38 (2) ◽  
pp. 471-490 ◽  
Author(s):  
DONALD M. WILSON
Keyword(s):  
Flight Control ◽  
Schistocerca Gregaria ◽  
Feedback Loops ◽  
Sensory Nerves ◽  
Surgical Removal ◽  
Flight Control System ◽  
Nervous Control ◽  
The Central Nervous System ◽  
Reflex Control ◽  
Stimulation Of

1. The co-ordination of the flight movements of Schistocerca gregaria Forskål was examined in order to determine the extent of central patterning and reflex control. 2. Electrical recordings from wing sensory nerves showed many units which responded to wing movements of various kinds. During flight the sensory discharge was timed to certain phases of the wing-beat cycle. 3. Surgical removal of the sources of timed input did not abolish patterned output, which resembled that during flight, but the frequency of cycling was considerably reduced. Either electrical stimulation of the nerve cord or continuous wind on the head could elicit the pattern. 4. A multiplicity of oscillators in the flight control system was demonstrated. 5. It is suggested that the basic co-ordination of flight is an inherent function of the central nervous system but that peripheral feedback loops influence the frequency of Operation and details of pattern.

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