This seems a bit nonsense question, however I am confused with this. I am doing the middle cerebral artery occlusion experiment using mice using intramural suture (filament) method. As we know the mice face towards the operator and when operator occlude the MCA (of mice) belonging his right side (operator) then it should be the left MCAo of mice, is not it? So the mice should circle (neurological behavior) to the right (left hemisphere impairment affects the function of left body parts). However, in my case when I occlude the right MCAo (my left side mice MCA while operating), the mice circles to the right. So could you explain where the problem is? Either I am doing left MCAo of mice (my left side while operating) or anything else?
Dear Philipp
This articleis the one that made me confused. The description in the video and the text state that it is left MCAo but the operator is performing tight (of mouse) MCAo while operating. That means the right or left MCAo depends upon the person's side and not in animals??
If you occlude the right MCA the mice will circle to the left (as in the video). The right hemisphere controls the left body side, so the mouse can only use it right side and will therefore circle to the left. In the video the mouse did not face the surgeon and therefore the right MCA was occluded (mouse side = surgeon side)!
Dear Benjamin
Yes I thought the same however the problem is in video it seems right MCAo, but it announce left MCAo and in that paper as well it is written that left MCAo is occluded.
Simple.
You put the filament in the mice' right MCA (at your left hand side) -> The animal's left limbs will be dysfunctional -> the mouse will circle counterclockwise. That's it.
Dear Bhakta and others, I know it has been 5 years since this was posted, but I Bhakta is right. There must be more to the direction than just the side of the paralysis. Here, I have attached a video of left MCAO (confirmed by other scientist, at 24h post MCAO) the mice all circle left. The right side is partially paralyzed, but they indeed all circle left. Perhaps there is some form of neglect going to the other side, that explains this?
Thank you Oiva ! I still think for this debate. Though many research believe that mice circles to the opposite of MCA occluded, I disagree with this. I believe that when right MCAO was done left body part is paralyzed and mice can not circle to the left (with paralyzed legs) rather it circle to the right (with non paralyzed right legs). Your video also prove this: mice are circling to the left with left MCAO.
I also run into the trouble about this. I occlude the rigth MCA (mice), while the most mice circle right, except for a few mice will circle left. I am confused if there is something wrong when I do the operation?
Hi Yijing.
I doubt there is a problem with occluding the intended artery. There simply has to be more to it, than what protocol papers describe. Perhaps the size of the infarction matters? Perhaps some mice did not receive enough post-operative pain medication, that could lead into crouching position, and are thus turning to the side with better working muscles (non-paralyzed side)? Or maybe some mice got too much pain medication, and they are pushing towards the other side (turning towards paralyzed side). In our case, all mice always turn towards infarct side. No question about it. If one lifts an MCAO mouse from it's tail the mouse tends to twist towards infarct side, because the mouse is trying to squeeze its abdominal/back muscles but the other side is somewhat paralyzed.
Probably you should check your mouse's brain to see if the vessel is penetrated or not. If it is penetrated, the bleeding will cause animals to circle to the contralateral side.
That is a great addition Zhiyong. Have you got any references or data to prove that? We could make a collaborative paper about it if there is no publications about it.
Thanks, Oliva. Currently no special paper is focused on this issue. According to my experience, the ipsilateral circling is often linked to the vascular penetration after doing the MCAO procedure. Yet no specific experiments were designed to test this phenomenon. Kind of tricky to well control the extent of penetration.
Hi Bhakta,
I'm also confused with the description about the video https://www.jove.com/video/2423/modeling-stroke-mice-middle-cerebral-artery-occlusion-with-filament
What did you observe in your later experiments? Is it correct that the mouse circles to the left when the left hemisphere are damaged?
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