I am wondering if anyone has seen the results of morris water maze like this;
- normal acquisition (decrease in escape latency)
BUT
- significant deficit in reversal learning
- normal memory extinction (mice do not go back to original platform)
I am having difficulty understanding logic behind this.
Can any of you give me some explanations?
Hi Yuka,
Reversal learning and extinction are different memory processes, both considered as part of the executive functioning but with different brain regions being involved.
For example, during reversal learning in the MWM, I published in this paper Article Quinolinic acid injection in mouse medial prefrontal cortex ...
that both prefrontal cortex and hippocampus were required to successfully perform the task.However, I performed other experiments with extinction learning in the contextual fear conditioning box or in the MWM, and found different results (not published). I myself did not investigate the brain areas involved in extinction, but it is considered to depend more strongly on the frontal lobe than in the hippocampus, whereas reversal learning requires both of them actively participating and communicating.
I hope this was of some help, feel free to ask me more questions.
Best,
Amira
Hi Yuka, interesting pattern of results. What was the treatment causing the dissociation of function? A lesion, a drug...??? In other words do you have control over the locus of brain damage? As a starter perhaps look over the literature on selective lesioning of the orbital frontal cortex, which seems to cause a selective impairment in reversal learning but not in extra-dimensional shifting of attention. In essence you should be looking at lesion studies among others that have revealed a dissociation of function, whereby performance is impaired under one test condition (reversal) but not under another different test condition (extinction). Good luck, Stephane
Stephane A Beaudin Thank you very much for your reply! I am using transgenic mouse model (camk2a Cre) and knock out our gene of interest. So the affected area should be mainly hippocampus and somewhat prefrontal cortex.
Amira Latif-Hernandez Hi Amira, thank you very much for your reply. Your research is really cool! Tbh, I was having difficulty finding articles that shed lights on reversal learning. Since I am new to a field of neuroscience (our lab is mainly focus on diabetes.), I felt very odd seeing my results as listed above. I am using camk2a-cre transgenic mouse model (mostly hippocampus and some prefrontal cortex). I assume other area of brain shouldn't be affected. Do you have any articles that you can suggest (including your publication) that may help me further investigate mechanism behind reversal memory?