Scientists direct insects by remote control

<body leftmargin="0" bgcolor="#000060" text="#FFFFFF" link="#FFFF00" vlink="#FF9900"> <b> <p class="MsoNormal"><font face="Arial" size="5">Scientists direct insects by wireless remote control</font></p> </b> <p class="MsoNormal"><font face="Arial" size="1">Posted April 9, 2005<br> Courtesy Cell Press<br> and World Science Staff<br> </font> <b> <font size="2" face="Arial"><br> Researchers have found a way to direct fruit flies’ behavior by shining laser light on them, the first time scientists have exercised wireless remote control over animals.<br> <br> The researchers made the flies jump, beat their wings, and fly on command by triggering genetic “remote controls” that they had installed in the insects’ brains. The research is published in the April 8 issue of the research journal <i>Cell</i>.<br> <br> The researchers, with Yale University in New Haven, Conn., said they hope the system will provide a valuable way to study how the activity of brain and nerve cells are related to specific behaviors. Such behaviors could range from simple movements to more complex activities like learning, aggression, and even abstract thought.<br> <br> Scientists have previously learned to control animals somewhat by installing tiny wires in their brains. But being able to do this without wires “would represent a significant step… to active and predictive manipulation of behavior,” wrote the researchers, Susana Lima and Gero Miesenböck.<br> <br> Miesenböck also said one could use this method to restore brain and nerve cell signals that have been lost due to injury or disease, such as in spinal cord trauma. But he added that this possibility is far-fetched just now.<br> <br> The remote control exploits the way that brain and nerve cells work. Both these types of cells, called neurons, contain tiny tubes through their outer covering called ion channels. Ion channels let specific molecules in and out of cells, and also exist in other types of cells. But in neurons, they’re a major part of the system for transmitting the chemical and electrical signals among cells that control our thoughts and feelings.<br> <br> Ion channels are often designed so that another specific type of molecule can latch onto one end of the channel or the other, and open or shut the opening like a key.<br> <br> Miesenböck and Lima devised a triggered molecular lock and key system to manipulate these cells. The “lock” was an ion channel that the flies were genetically engineered to produce in one brain area. The “key” was a molecule, called ATP, that would bind to and open the lock. Laser light was the trigger that brought the key to the lock, by removing chemicals that kept the key caged in until the right time.<br> <br> Miesenböck said one of the most difficult parts of the experiment was deciding which cells to target with the remote control system. They eventually decided to target a small set of nerve cells in the fly called the giant fiber system. <br> <br> The giant fiber system controls very specific movements that are stereotyped, or done according to a set pattern, such as escape movements, jumping, and the beginnings of flight. If the flies engaged in these behaviors after the giant fiber neurons had been outfitted and “operated” with the remote control, Miesenböck and Lima reasoned, they could be sure that their system was working.<br> <br> After genetically engineering the flies to have the ion channel in the giant fiber system cells and using the tiniest of injections to place the caged ATP inside the flies, the researchers shone a ultraviolet-wavelength laser in brief pulses at the flies trapped inside a glass-domed arena. On command, the flies began a series of escape movements--extending their legs, jumping, and opening and rapidly flapping their wings.<br> <br> The laser-triggered remote controls in the giant fiber system worked about 63 percent of the time, while remote controls placed in other nerve cells that were targets of the giant fiber system worked 82 percent of the time, the researchers concluded. Lima and Misenböck also equipped another set of nerve cells called dopaminergic neurons with the remote controls, boosting the flies’ activity levels and changing their flight paths.<br> <br> Misenböck said the triggered behaviors can last seconds or continue for minutes, depending on whether the neural circuit activated by the remote control has feedback loops that keep the circuit. “In the case of the flight circuits,” he said, “it is like pushing a swing. One initial kick and it keeps swinging back and forth for a while.”</font></b> </p> </body>