brains registered the activity of neurons. Electrodes were also placed on feeding muscles to monitor the activity of the proboscis a long tube that a moth uses for feeding when the insects were exposed to different odors and to sugar. The researchers wanted to see how a moth's nervous system changed its response to an odor that was associated with food and how the moth responded behaviorally to that odor.
The moths were restrained in plastic tubes, leaving the antennae and proboscis accessible. Electrodes were inserted into each insect's head; Daly said that brain recordings could be made for up to 48 hours in these conditions. These moths normally live for a few days as adults.
The investigators put the bound moths through different odor conditioning trials: one created a clear relationship between an odor and food. In this case, the researchers wanted to see what happened in the brain and proboscis before, during and after the moths were exposed to the food-associated odor. In the second trial, moths were exposed to two odors, but only one predicted food. Both trials exposed moths to a series of 20 millisecond-long puffs of odor.
When odor predicted food, the researchers saw a significant and progressive increase by about 60 percent in the number of neurons responding to the odor. This increase in the neural network response indicated that the moths learned to associate the odor with food.
The researchers also saw striking differences in neuronal activity between the odor that predicted food and the odor that had nothing to do with food.
"More neurons were recruited into action when a moth smelled the odor connected to food," Daly said. "After a few exposures to this odor, moths automatically started sucking for the food, even when they weren't rewarded with food. They also learned to not respond to the odor that was unrelated to food.
"After learning, the way their nervous system responded to odor changed," he sPage: 1 2 3 Related biology news :1
Contact: Kevin Daly
Ohio State University
. Student science contest participation influences study, career choices, alumni say2
. New study shows hope for treating inhalant abuse3
. International study findings link acne-like rash to effectiveness of new targeted cancer treatment4
. Cigarette smoke causes breaks in DNA and defects to a cells chromosomes, Pitt study finds5
. New study indicates arsenic could be suitable as first-line treatment in type of leukaemia6
. Phase II trials of second-generation antisense cancer drug planned following successful early study7
. Preclinical safety study shows adipose-derived stem cells improve heart function after heart attack8
. Indiana University, EPA to study airborne PCBs9
. K-State, other universities to study how climate affects plant evolution10
. USC study links historical increases in life span to lower childhood exposure to infection11
. Washington University in St. Louis leads group studying aging process