Impaired learning can take different forms depending on the nature of the underlying deficit. For an example, let’s take a look at a recent paper (Mohn et al., 2014). Without getting too deep into this involved study, I’ll laydown the basics.
Autism Spectrum Disorders and learning disabilities have been linked to mutations that delete a particular gene (adenomatous polyposis coli, for those of you who are interested).
The authors created a knockout mouse for this gene
They tested learning and memory in these mice using the barnes maze
They also did a lot of other stuff I’m not talking about here, such as measuring levels of long term potentiation in the hippocampus and synaptic spine densities in cortex and hippocampus.