MSGID: 1:317/3 648007fa   
   PID: hpt/lnx 1.9.0-cur 2019-01-08   
   TID: hpt/lnx 1.9.0-cur 2019-01-08   
    Electrical synapses in the neural network of insects found to have   
   unexpected role in controlling flight power    
      
     Date:   
         June 6, 2023   
     Source:   
         Johannes Gutenberg Universitaet Mainz   
     Summary:   
         A team of experimental neurobiologists and theoretical biologists   
         has managed to solve a mystery that has been baffling scientists   
         for decades.   
      
         They have been able to determine the nature of the electrical   
         activity in the nervous system of insects that controls their   
         flight. They report on a previously unknown function of electrical   
         synapses employed by fruit flies during flight.   
      
      
         Facebook Twitter Pinterest LinkedIN Email   
      
   ==========================================================================   
   FULL STORY   
   ==========================================================================   
   A team of experimental neurobiologists at Johannes Gutenberg University   
   Mainz (JGU) and theoretical biologists at Humboldt-Universita"t zu Berlin   
   has managed to solve a mystery that has been baffling scientists for   
   decades. They have been able to determine the nature of the electrical   
   activity in the nervous system of insects that controls their flight. In   
   a paper recently published in Nature, they report on a previously unknown   
   function of electrical synapses employed by fruit flies during flight.   
      
   The fruit fly Drosophila melanogaster beats its wings around 200 times   
   per second in order to move forward. Other small insects manage even   
   1,000 wingbeats per second. It is this high frequency of wingbeats that   
   generates the annoying high-pitched buzzing sound we commonly associate   
   with mosquitoes.   
      
   Every insect has to beat its wings at a certain frequency to not get   
   "stuck" in the air, which acts as a viscous medium due to their small   
   body size. For this purpose, they employ a clever strategy that is widely   
   used in the insect world.   
      
   This involves reciprocal stretch activation of the antagonistic muscles   
   that raise and depress the wings. The system can oscillate at high   
   frequencies, thus producing the high rate of wingbeats required for   
   propulsion. The motor neurons are unable to keep pace with the speed   
   of the wings so that each neuron generates an electrical pulse that   
   controls the wing muscles only about every 20th wingbeat. These pulses   
   are precisely coordinated with the activity of other neurons. Special   
   activity patterns are generated in the motor neurons that regulate the   
   wingbeat frequency. Each neuron fires at a regular rate but not at the   
   same time as the other neurons. There are fixed intervals between which   
   each of them fires. While it has been known since the 1970s that neural   
   activity patterns of this kind occur in the fruit fly, there was no   
   explanation of the underlying controlling mechanism.   
      
   Neural circuit regulates insect flight Collaborating in the RobustCircuit   
   Research Unit 5289 funded by the German Research Foundation, researchers   
   at Johannes Gutenberg University Mainz and Humboldt-Universita"t zu Berlin   
   have finally managed to find the solution to the puzzle. "Wing movement   
   in the fruit fly Drosophila melanogasteris governed by a miniaturized   
   circuit solution that comprises only a very few neurons and synapses,"   
   explained Professor Carsten Duch of JGU's Faculty of Biology. And it is   
   extremely probable that this is not just the case in the fruit fly. The   
   researchers presume that the more than 600,000 known species of insects   
   that rely on a similar method of propulsion also employ a neural circuit   
   of this kind.   
      
   Drosophila melanogaster is the ideal subject for research in the field   
   of neurobiology as it is possible to genetically manipulate the various   
   components of its neural circuit. Individual synapses can be switched   
   on and off and even the activity of individual neurons can be directly   
   influenced, to name just two examples. In this case, the researchers   
   used a combination of these genetic tools to measure the activity and   
   electrical properties of the neurons in the circuit. Thus they were able   
   to identify all the cells and synaptic interactions of the neural circuit   
   that are involved in the generation of flight patterns. As a result,   
   they found that the neural network regulating flight is composed of   
   just a small number of neurons that communicate with each other through   
   electrical synapses only.   
      
   New concepts of information processing by the central nervous system   
   It had previously been assumed that when one neuron fired, inhibitory   
   neurotransmitter substances were released between neurons of the flight   
   network, thus preventing these from firing at the same time. Using   
   experimentation and mathematical modeling, the researchers have been   
   able to show that such a sequential distribution of pulse generation can   
   also occur when neural activity is directly controlled electrically,   
   without the presence of neurotransmitters. The neurons then create a   
   special kind of pulse and 'listen' closely to each other, especially if   
   they have just been active.   
      
   Mathematical analyses predicted that this would not be possible with   
   "normal" pulses. Hence, it would appear unlikely that transmission between   
   neurons in a purely electrical form would result in this sequenced firing   
   pattern. In order to test this theoretical hypothesis experimentally,   
   certain ion channels in the neurons of the network were manipulated. As   
   expected, the activity pattern of the flight circuit became synchronized   
   -- just as the mathematical model had predicted. This experimental   
   manipulation caused significant variations in the power generated during   
   flight. It is thus apparent that the desynchronization of the activity   
   pattern determined by the electrical synapses of the neural circuit   
   is necessary to ensure that the flight muscles are able to generate a   
   consistent power output.   
      
   The findings of the team based in Mainz and Berlin are particularly   
   surprising given that it was previously thought that interconnections   
   by electrical synapses actually result in a synchronized activity of   
   neurons. The activity pattern generated by the electrical synapses   
   detected here indicates that there may well be forms of information   
   processing by the nervous system that are as yet unexplained. The same   
   mechanism may not only play a role in thousands of other insect species   
   but also in the human brain, where the purpose of electrical synapses   
   is still not fully understood.   
      
       * RELATED_TOPICS   
             o Plants_&_Animals   
                   # Developmental_Biology # Birds #   
                   Insects_(including_Butterflies) # Behavioral_Science   
             o Earth_&_Climate   
                   # Energy_and_the_Environment # Weather # Atmosphere #   
                   Environmental_Science   
       * RELATED_TERMS   
             o Chemical_synapse o Neuron o Sympathetic_nervous_system   
             o Beetle o Whooping_Crane o Flying_squirrel o   
             Peripheral_nervous_system o Parasympathetic_nervous_system   
      
   ==========================================================================   
   Story Source: Materials provided by   
   Johannes_Gutenberg_Universitaet_Mainz. Note: Content may be edited for   
   style and length.   
      
      
   ==========================================================================   
   Journal Reference:   
      1. Silvan Hu"rkey, Nelson Niemeyer, Jan-Hendrik Schleimer, Stefanie   
         Ryglewski, Susanne Schreiber, Carsten Duch. Gap junctions   
         desynchronize a neural circuit to stabilize insect flight. Nature,   
         2023; 618 (7963): 118 DOI: 10.1038/s41586-023-06099-0   
   ==========================================================================   
      
   Link to news story:   
   https://www.sciencedaily.com/releases/2023/06/230606111652.htm   
      
   --- up 1 year, 14 weeks, 1 day, 10 hours, 50 minutes   
    * Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1:317/3)   
   SEEN-BY: 15/0 106/201 114/705 123/120 153/7715 218/700 226/30 227/114   
   SEEN-BY: 229/110 112 113 307 317 400 426 428 470 664 700 291/111 292/854   
   SEEN-BY: 298/25 305/3 317/3 320/219 396/45   
   PATH: 317/3 229/426