The neuroimaging of long-term memory encoding processes

There needs to be more crosstalk between the lesion and functional neuroima ging memory literatures. This is illustrated by a discussion of episode and fact encoding. The lesion literature suggests several hypotheses about whi ch brain regions underlie the storage of episode and fact information, whic h can be explored by functional neuroimaging. These hypotheses have been un derexplored because neuroimaging studies of encoding have been insufficient ly hypothesis-driven and have not controlled encoding-related processes suf ficiently well to allow clear interpretations of results to be made. Nevert heless, there is good evidence that certain kinds of associative encoding a nd/or consolidation are sufficient to activate the medial temporal lobes, a nd preliminary evidence that some kinds of associative priming may reduce a ctivation of this region. It remains to be proved that attentional orientin g to certain kinds of novel information activates the medial temporal lobes . Evidence is growing that the HERA model, developed from neuroimaging rath er than lesion data, requires modification and that frontal cortex encoding activations are probably caused by executive processes that are important in effortful memory processing. Neuroimaging studies allow the detection of encoding-related activations in previously unexpected brain regions (e.g. parietal lobes) and, in turn, these findings can be explored with lesion st udies.