What have ablation studies told us about the neural substrates of stimulus memory?

Recent studies examining the neural substrates of stimulus memory in monkeys have found that the 'rhinal' cortex (i.e. the entorhinal and perirhinal cortex) makes a pivotal contribution to memory. Indeed, the rhinal cortex appears to be the only critical medial temporal lobe structure for stimulus recognition and certain kinds of associative memory as well. Thus, the mnemonic contributions of certain medial temporal structures, especially the amygdala and hippocampus, appear to have been overemphasized, and should be reconsidered.