These past two weeks have been heavily focused on getting the W-Maze rats completed with their track sessions. Our data has to be analyzed and consolidated by the first week of May, and our results have to be final and ready to share as well. Our lab is attanding a conference where we were asked and invited to share our research. We will be sharing in the form of a poster presentation.
In addition to the stress of completing our research, I was also given a new cohort of 10 rats to train. They are now on the Linear Track. Luckily, this cohort so far learns a lot quicker than the previous one. I have a little over a week left in the lab. Next week, week 12, will be my last blog post. I will share the data that I have included in my powerpoint presentation.
This week was slightly chaotic due to everything that was taking place in the lab. I continued running some of the rats on the Linear Track and also some on the W-maze. The Linear Track rats are improving, but the W-maze rats are not learning their task too well. However, we were not too focused on the Linear Track and W-maze this week because about 15 rats were undergoing surgery for a new project. Unlike the hyperdrive surgery where the rats are implanted with permanent electrodes, this surgery consists of injecting a certain substance that can later be used to locate areas of brain activity under certain conditions. I was allowed to watch the surgeries take place after running my rats on the mazes. I got to see the craniotomy (exposing the brain by removing a part of the skull) and the suturing (closing the head back up).
This week was like any other… Linear Track and W-Maze. Because two of the rats reached learning criteria, they were put on the W-Maze. They are doing well on the W-Maze. Thursday was pretty exciting because another team needed help on the Water Maze, so I was able to help them when I finished up with my rats. I had not done the Water Maze for a few weeks! My favorite test for the rats is actually the Water Maze. It is very fun to watch the rats learn how to use visual cues to swim to a hidden platform. There happened to be a stark difference between the performance of the younger rats and the older rats. The older rats were a lot slower and most could not find the platform even after a minute of swimming. This is all I have to say for this week!
The hyperdrive implant surgery was successful and the rat is currently in recovery. I was invited to watch the surgery, and the woman who administered and drove the surgery graciously explained to me the step by step process as she was doing the surgery. I also had the honor of holding a light an inch above the opened and bloody head! Luckily, I was not squeamish. To me, the most interesting part of the surgery was when the head was already cut open and the surgeons had to carefully circumvent major blood vessels while finding the part of the brain they were going to implant in. All in all, the surgery went well and the rat’s breath and heartrate were constant throughout. No major vessels were hit, which would normally result in uncontrollable bleeding, so that was a relief! The rat is on antobiotics as a precautionary against infection. As Dr. Carol Barnes says, we will soon be able to listen to the “symphony of the brain.”
This is the closest image i could find to the hyperdrive implant:
Besides the surgery, this week was also a good one for the second cohort of rats. They continued on the linear track and a few have reached learning criteria! This means we will be able to put them on the W-track sooner than we thought.
The first cohort of rats is officially done with the mazes. Now we will be analyzing the data from the experiment. We moved those rats downstairs and transferred them to new cages because we will no longer be using them for behavioral studies. As for the second cohort of rats, they are learning on the Linear Track. Each rat trains for 30 minutes a day. The learning criteria for these rats is 1.5 laps per minute. They will require many more sessions to get to that point. So far they have only completed 9 sessions. At the beginning of the week, almost none of the rats were moving on the track, but now almost all of them are. They are slowly improving.
This week in the lab, the first cohort of rats continued training on the W-Maze Alternation Task. Significant progress has been made on the W-Maze. Almost all of the rats have reached learning criteria and get faster, also making fewer errors, each day! However, one of the rats had not made any effort to move on the maze. We figured he was just not hungry because he had no motivation to move on the track; however, after dropping his weight/food for a day and testing him again, we decided to throw out all of his data and give him to a different lab where he may be of greater use. All in all, this cohort of rats is almost done with maze-ing!
The second cohort of rats began habituation, which is the phase about 4 weeks behind the first cohort of rats. As for habituation with the second cohort of rats, all of the rats are getting accustomed to the height, environment, and reward system on the linear track. Some of the rats are timid with obvious signs like hunched backs and no desire to move. One of the rats has porphyrin (red substance that looks like blood) around his right eye meaning he is stressed. Another two rats have discolored (pink-ish) hair patches on their heads which is also a symptom of stress. Their weights are also starting to drop. As I have said before, we want their weights to drop (a healthy amount) in order to motivate them on the reward based mazes and tracks.
In other news, three rats peed on me this week (haha, how rude). Also, the research specialist who I work with has been prepping for a rat surgery where she will implant a hyperdrive into a rat’s brain to be able to monitor brain signals and neurons and all that fun stuff. Many rats in the lab already had this surgery, but this rat in particular will be kept for us to monitor because the focus is the hippocampus (memory). I am particularly excited because I was asked to watch the surgery! I will definitely give an update on that, but the surgery will happen late March.
*Unfortunately, next week I will not be in the lab or blogging because it is spring break at the UofA and mostly everyone is out of the lab. Fortunately, I have next week off and I’m going to Mexico for a MUCH NEEDED break because I have been going to the lab every day since school ended*
To end this post, here are more pictures of my rats:
The first cohort of rats (the ones already on the W-track) continued training on the track this week. As I mentioned before, each rat trains for an hour a day. So, I basically spent all day watching seven rats on the track each day this week. Some rats have been learning and mastering the patterns on the maze, while the others are miserably failing.
The second cohort of rats took a break from all activity this week.
One thing we had been focusing on this week were the rats’ diets. They were losing weight extremely fast and their weights were dangerously low. However, we want the rats to be hungry because the task is reward based, food being their motivation. That being said, we want them to be hungry every day, but we do not want them to get sick and weak. We had to take a day break from training them because we wanted them to get their weight back up. After that break, their weights did go back up and we were able to train them.
As I mentioned in my last post, I am working with two different cohorts of rats. The first group of rats was introduced to the lab a few months ago and I have already completed multiple stages of the experiment with them: the Water Maze, Habituation, Linear Track, and currently the W-maze Alternation task. The second group of rats was just introduced to the lab last week which is why they recieved health checks.
This week, the second group of rats completed the Water Maze. The Water Maze lasts a week, and is crucial in testing the rats’ cognitive abilities, visual acuity, and motor skills. This test decides the yoked pairs (one young and one old rat). Yoked pairs are used because even though the research is focused on the interaction between the hippocampus and PFC, the research is also looking at the changes in the brain that occur through the aging process, so we pair a young rat and old rat with similar performance. Lastly, the Water Maze can also be used to assess if a rat is blind. If we find a rat to be blind, we cannot use the specific rat for the upcoming experiments.
The first few days of the water maze test spatial memory. The platform is set at a single location for these first few days. We put a paint in the pool that makes the water opaque so the platform is hidden. Around the pool of water are visual cues in hopes that the rats will take mental note of where the platform is, so that with each trial when the rat is dunked into the pool at a different insertion point, they can find the platform in a shorter amount of time. The time it takes to find the platform is recorded for each trial. Following these few days of testing spatial memory is a day of testing visual acuity. Instead of keeping the platform in a set place and hidden, the platform is visible and changes location for each trial. This solely tests whether the rats can find the platform with their eyes.
This is a digital sketch of the Water Maze I found online:
Between each trial the rats are held in temperature-controlled case. They all cozy together to keep warm. I took a picture of them because it was so cute.
Unfortunalty after completing the last trial of the water maze, one of rats was very weak and sick looking. We noticed his eyes were struggling to keep open and the color was changing from red to pale pink. His head began rocking and his body could not maintain balance. After trying to keep him stable and warm, we were told he probably had a brain tumor because of how he was behaving (these rats also get tumors often). He had to be put down. I was very sad to see him go because he was so cute and sweet (not to sound weird but I grow attached to these rats). Anyways, his brain is now in the fridge for us to examine or dissect if we wish (silver lining?!).
I thought I’d mention that the Barnes Lab has frequent meetings to bring the Barnes Lab researchers together to discuss progress made in the lab and also current studies, articles, and events occuring in the neurobiology world.
I find these meetings quite interesting. Everyone in the conference room got a chance to go around and give a brief desciption of their current experiments and their goals with the research. I would mention some that I have heard, but I’m not sure if I am allowed to discuss that information; however, everyone shared very exciting things.
One researcher in the lab mentioned that she had just come back from a neuroscience conference in France. Because she is a bilingual researcher, she was invited to present a topic. Also, Dr. Carol Barnes came back from a neuroscience conference in Europe and brought back chocolate for everyone!
A big part of the meeting was discussing future goals for the lab. Funding for research is crucial, so how to find large donors and sponsors was also touched on.
This week was very fun for me in the lab. The rats reached learning criteria on the Linear Track (which I talked about in week 2) and moved on to the next stage, the W-Maze Alternation Task.
The completion of the W-maze Alternation Task demonstrates how the hippocampus and pre-frontal cortex (PFC) interact. An animal must access memories from previous trials which is dependent on the hippocampus. Then, an animal must utilize this information to guide a choice between the two side arms of the track which is dependent on the PFC.
The rats are tested on the W-track for 14 consecutive days, so there are 14 sessions.
Here is a digital sketch of the w-maze/track from the research protocol:
In the research protocol, the W-maze is decribed as an automated system controlled by the Arduino Uno microcontroller. It consists of three solenoids, three feeder dishes, tubing, and three infrared motion sensors hooked up to the microcontroller. On the end of each arm of the maze, there is a food dish and an infrared motion sensor. When the rat breaks the plane of the sensor, it will trigger the opening of the solenoid to dispense vanilla Ensure into the feeder dish. Ensure is the same food reward the rats recieved on the Linear Track.
A computer application, coded by my very smart research advisor, tells the experimenter how many correct patterns (laps) were completed and how many errors were made. Also, a camera mounted on the ceiling records video data for future behavioral analysis. This camera system is also helpful because I get to live-watch the rat in action on the track/maze instead of standing in the room as that woud distract the rat.
Correct Patterns would look like:
Given that this was the first week, many incorrect patterns were made. Incorrect patterns are when the rats go in a u-pattern (two arms) in a row instead of a w-pattern (three arms). Another incorrect pattern could be going back and forth on the same arm twice. The goal is that each day the rat will improve because it can retrieve memories to make correct choices. This again highlights how the hipocampus and PFC are involved.
Last week I mentioned that we recieved new rats to add to our experiment. These new rats have yet to complete the Linear Track and the W-maze. In my next post I will be talking about what I did with the new rats this week!