The effects of methyl mercury on spatial memory in zebra finches: Weeks 8-10

The last two weeks of my summer research were spent mainly retesting birds, entering all the data into an excel spreadsheet, and learning the procedure to preserve the brains of the zebra finches we tested. This research is studying two components: the birds spatial memory, and the structure and immunochemistry of their hippocampus, which is the structure believed to be responsible for spatial memory in avian species. The main goal of the research was to tie the effects that mercury has on spatial memory and the hippocampus together, in order to see if it negatively affects both their performance and the structural integrity of their hippocampus. During these last two weeks, Neil and I learned the process for preserving the brains of the zebra finches so they can be studied for this at a later date. My partner Neil Huckstep plans to take these brains back to his lab at Virginia Tech in order to study them more in depth. While I learned the basic procedure for preserving them, my partner is going to be the one actually preforming the procedure next week since I am leaving this coming Friday.

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The effects of methyl-mercury on spatial memory in zebra finches – Week 6-8

During these weeks of my summer research, I had begun to run the mercury-dosed birds through the spatial memory test. I had to be careful any biases I had about the outcome of their trials wouldn’t affect how I tested them, because the goal of my research is to determine if there actually is a difference between the spatial memory capabilities of mercury-dosed birds compared to normal ones. Since I predicted that their capabilities would be decreased, I had to be wary of whether or not I was biased about the way I recorded data, as experimenter bias could make me interpret the results I get in a way that is beneficial to me. Thankfully however, I had the feeling that I was being as objective as a possibly could, and it helped that the data I’m collecting for this particular spatial memory test is pretty objective with little room for bias affecting it.

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The effects of methyl-mercury on spatial memory in zebra finches – Week 4-6

During these weeks of the summer, we finally began running trials on the sets of mercury and control birds designated for this experiment. My partner, Neil Huckstep, was out of town during these weeks, so another member of our lab, Capwell Taylor came in and helped me run trials. Essentially what we decided to do was to run trials in the morning and the afternoon in order to get through all the birds we needed to test this summer, and this proved to be very necessary. Otherwise, given how long it took for us to finish all trials using this plan, we would not have been able to finish in time if we just ran four birds a day. So it was very helpful to have Capwell fill in for Neil so we could run 8 birds a day instead of four. We started off by testing 8 mercury birds the first week and 6 the next week, which we later learned from my PI, might not have been the best idea. According to him, since conditions may change over the few weeks it takes to finish the control birds and move onto the mercury birds, it may have been better to do four control birds and four mercury birds each week to negate the possible effects of changing conditions. However, given the small sample size and the amount of time it took to finish the control birds, it’s likely that running all the control birds at once wasn’t problematic.

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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.

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Effects of Methyl-mercury on spatial-memory in Zebra Finches: Summary of first two weeks

The subject of my summer research has changed a bit since I originally posted my abstract at the end of the spring semester. I still am studying the effects that methyl mercury has on the cognitive abilities of zebra finches, but the main cognitive process I am studying is spatial memory. Spatial memory is especially important for avian species, since many food-storing and migratory birds rely on it in order to retrieve caches of food they have stored or to remember the location of where they migrate. Since the subject of my research changed a bit, I spent the first week or so of my summer research conducting a lot of primary literature search, trying to better understand the science behind what I was studying, and also to determine why what I was researching was important to study. This really helped set the framework for how I wanted to approach my research, and gave me a better understanding of the mechanisms at work.

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