Temperature Dependence of the Neural Control of the Moth Flight System

1970 ◽  
Vol 53 (3) ◽  
pp. 629-639
Author(s):  
JAMES L. HANEGAN ◽  
JAMES EDWARD HEATH

1. The transition from the warm-up motor pattern to the flight motor pattern in the saturnid moth H. cecropia, is described. 2. The transition from warm-up to flight was found to be dependent on the temperature of the thoracic ganglia. 3. A model to account for the two different motor output patterns and the transition of the warm-up pattern to the flight pattern is proposed.

1995 ◽  
Vol 198 (4) ◽  
pp. 869-875 ◽  
Author(s):  
M Lorez

Corrective flight steering with the hindlegs was investigated in intact tethered flying locusts inside a wind tunnel as well as in animals dissected for intracellular recording and showing fictive flight activity. In intact tethered flying animals, activity in the second coxal abductor muscle (M126) was highly correlated with hindleg steering and was coupled to the elevator phase of the flight cycle. Fictive flight and steering could also be elicited in animals dissected for intracellular recording of motoneurones innervating M126. During fictive flight activity, motoneurones 126 were rhythmically excited in the elevator phase, presumably from central elements of the neuronal oscillator generating the flight motor pattern, as is the case for motoneurones innervating wing muscles. During fictive straight flight, this input was subthreshold, and it could be demonstrated that simulated deviation from the flight course resulted in recruitment of motoneurones 126. Statistical analysis of the latencies of fast muscle spikes in M126 and in one wing elevator muscle showed that both received common input during flight steering. One source of this common input was identified as the sensory information from the lateral ocelli, which play an important role in the detection of course deviation. The experiments demonstrated that processing in the sensory-motor system for hindleg steering is probably organized in a very similar way to that responsible for steering with the wings.


1985 ◽  
Vol 53 (1) ◽  
pp. 110-128 ◽  
Author(s):  
R. M. Robertson ◽  
K. G. Pearson

Circuitry in the flight system of the locust, Locusta migratoria, was investigated by use of intracellular recording and staining techniques. Neuronal connections were established by recording simultaneously from neuropile segments of pairs of identified interneurons. Brief depolarizing current pulses delivered to interneurons 301 and 501 reset the flight rhythm in a phase-dependent manner, thus establishing the importance of these neurons in rhythm generation. Interneuron 301 was found to make a strong delayed excitatory connection with 501 and to receive a short-latency inhibitory connection from 501. The circuit formed by 301 and 501 appears suited for promoting rhythmicity in the flight system. The delayed excitatory potential recorded in 501 following each spike of 301 was reversed by hyperpolarizing 501. This potential and short-latency inhibitory postsynaptic potentials from 301 to other interneurons were blocked with the application of picrotoxin. We conclude that the delayed excitation is produced via a disynaptic pathway from 301 to 501, with 301 inhibiting in a graded manner the tonic release of transmitter from one or more unidentified intercalated neurons. Interconnections between the 301-501 circuit and other identified interneurons were discovered. This circuitry can account for two features of the flight motor pattern recorded in deafferented preparations. These features are the constant-latency relationship between depolarizations in elevator and depressor motoneurons and the relatively constant duration of depressor motoneuron bursts. The locust flight system shares general features with other described rhythm-generating systems. These include the occurrence of graded interactions, the probability of multiple oscillatory mechanisms, and a predominance of inhibitory connections. Its uniqueness lies in the way that components and processes are assembled and operate.


1991 ◽  
Vol 157 (1) ◽  
pp. 313-333 ◽  
Author(s):  
ANSGAR BÜSCHGES ◽  
KEIR G. PEARSON

Previous investigations on the flight system of the locust have found that removal of the wing tegulae in mature locusts (Locusta migratoria) results in an immediate change in the flight motor pattern: the wingbeat frequency (WBF) decreases, the interval between the activity of the depressor and the elevator muscles (the D-E interval) increases, and the phase of the elevator activity in the depressor cycle increases. Here we report the results of a detailed quantitative analysis of these changes. We also examined the flight motor pattern for up to 14 days after removal of the tegulae and found that the changes caused by this operation were not permanent. Beginning on the first day after the operation there was a time-dependent recovery of the WBF, the D-E interval and the phase towards their normal values. In about 80% of the experimental animals the flight motor pattern recovered almost completely. Intracellular recordings from elevator motoneurones showed that this recovery was associated with changes in the pattern of excitatory input to these motoneurones. The modification of activity in elevator motoneurones was dependent on afferent input since complete deafferentation of recovered animals resulted in a motor pattern similar to that following deafferentation of normal animals.


1998 ◽  
Vol 76 (4) ◽  
pp. 660-667 ◽  
Author(s):  
Christine E Gee ◽  
Kelly L Shoemaker ◽  
R Meldrum Robertson

The flight system of Locusta migratoria is widely used to investigate the principles of sensory-motor control. The four tegulae are proprioceptors of the flight system that are active during the downstroke and provide afferent input to flight-system neurons. While the role of the hindwing tegulae in the flight motor pattern has been well characterized, the role of the forewing tegulae is unclear. We tested whether the forewing tegulae may be more important for the generation of intentional steering manoeuvres than for generation of the basic flight motor pattern. Following ablation of the forewing tegulae, tethered flying locusts continued to generate characteristic intentional steering manoeuvres in open-loop conditions. In contrast, we found that locusts were less likely to sustain unrestrained free flight following ablation of the forewing tegulae. We also found that the number of spikes in a forewing depressor muscle increased, as did the hindwing to forewing delay in elevator-muscle activation after ablation of the forewing tegulae. We conclude that the forewing tegulae promote free flight in locusts and we discuss the role they may play in locust flight.


1986 ◽  
Vol 55 (4) ◽  
pp. 678-688 ◽  
Author(s):  
K. T. Sillar ◽  
P. Skorupski

A preparation is described in which the thoracic ganglia of the crayfish are isolated together with the thoracocoxal muscle receptor organ (TCMRO) of the fourth leg. This preparation allows intracellular analysis of both centrally generated and reflex activity in leg motor neurons (MNs). The isolated thoracic ganglia can spontaneously generate a rhythmic motor pattern resembling that used during forward walking (Fig. 4). This involves the reciprocal activity of promotor and remotor MNs, with levator MNs firing in phase with promotor bursts. Stretch of the TCMRO in quiescent preparations evokes a resistance reflex in promotor MNs (Fig. 6). In more active preparations the response is variable and often becomes an assistance reflex, with excitation of remotor MNs on stretch (Fig. 7). When rhythmic motor patterns occur, the neuropilar processes of the S and T fibers receive central inputs that are strongly correlated with the oscillatory drive to the MNs and probably have the same origin (Figs. 8 and 9). Central inputs to the S and T fibers occur in opposite phases within a cycle of rhythmic motor output. The S fiber is depolarized in phase with promotor MNs and the T fiber in phase with remotor activity. The input to the T fiber is shown to be a chemical synaptic drive that has a reversal potential approximately 14 mV more depolarized than the fiber's resting membrane potential. This input substantially modulates the amplitude and waveform of passively propagated receptor potentials generated by TCMRO stretch (Fig. 11). It is argued that the central inputs to the TCMRO afferents will modulate proprioceptive feedback resulting from voluntary movements.


1968 ◽  
Vol 48 (1) ◽  
pp. 89-109
Author(s):  
ANN E. KAMMER

1. The patterns of muscle activity during warm-up were compared to those of flight. In the skipper Hylephila phylaeus and in the hawk moths Celerio lineata and Mimas tiliae the intervals between bursts of muscle potentials are the same as the wingbeat periods of flight at the same thoracic temperature, and the burst length is the same as in flight. In saturniids the period and burst length are both shorter during wing-vibrating than during flight. 2. During wing-vibrating the amplitude of the wing movement is small, and some of the muscles which are antagonists in flight are active simultaneously. In Hylephila phylaeus and Celerio lineata there is a phase change between some synergistic muscles, while some antagonistic pairs retain the phase relationships of flight. During wing-vibrating in Mimas tiliae and in saturniids all the motor units sampled were active at the same time. 3. In M. tiliae a variety of phase relationships intermediate between those of wing-vibrating and flight were observed, including a case of ‘relative co-ordination’ between motor units in the mesothorax. The results exclude the possibility that a single pace-making centre drives the motor neurons in the flight pattern. 4. A model of the central nervous interactions which generate the observed motor patterns is proposed. It is postulated that a small group of positively coupled neurons produces bursts of impulses at the wingbeat frequency and that these groups interact to generate the phase relationships seen during warm-up and flight.


1991 ◽  
Vol 168 (4) ◽  
pp. 483-490 ◽  
Author(s):  
W. Kutsch ◽  
R. Kittmann
Keyword(s):  

1979 ◽  
Vol 130 (1) ◽  
pp. 29-37 ◽  
Author(s):  
Ann E. Kammer ◽  
Sue C. Kinnamon
Keyword(s):  

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