Effects of Methyl-mercury on spatial-memory in zebra finches: Summary of weeks 3-4

After I did my own background research for the first two weeks and began setting up the testing apparatus, it was now time to begin running test trials on a few birds that weren’t going to be used in the experiment. We needed to establish a definite and set-in-stone protocol so we wouldn’t be changing things around during real trials, so we used these practice trials to do just that. We had a protocol given to us from my partner Neil’s advisor from Virginia Tech, so we had to adjust it to fit the criteria needed for the experiment. The experiment itself involves teaching the birds to remove a cover from a block with food inside of it. Once it has done this, those same blocks are placed in the four corners of the cage, and we record which blocks it goes for to get food. This teaches the bird how to eat from the four corners of the cage, and it establishes which corners the bird might have a preference or a dislike for, which is important for the next phase of the experiment. In this final phase, we remove food from three of the corners and bait it toward one of them. During this phase, we measure how long it takes for them to eat from the baited corner, how many mistakes it makes (eating from other corners) before it finally eats from the correct one. This is a test of spatial memory because it requires the bird to learn that the food is located in a certain corner, and to accurately remember this fact by using spatial cues around them in their environment. We are essentially trying to test whether or not birds dosed with sub-lethal levels of mercury have reduced spatial memory capabilities compared to birds who are not on a mercury-infused diet.

We had to make some adjustments to the protocol given to us by Neil’s advisor, and these two weeks during the summer were important for making those modifications. The two most important modifications made were extending the amount of time we fasted the birds, and establishing criteria for failing birds out of trials if they weren’t preforming adequately. We found that the birds preformed better when we increased the amount of time they were fasted, because this made them more food motivated. Establishing criterion for failing out birds was also important because we found that some birds were just unable to find the baited corner at all or weren’t even interested in the tasks. Because of this, we had to set up some guidelines so we wouldn’t waste our time running these birds over and over again.

Comments

  1. What a brilliant cognitive ability to study. I’ve always been intrigued by how species process their physical surroundings and function in relation to them. Was there a specific species of bird you dealt with?