Dissociation between memory retention across a delay and pattern separation following medial prefrontal cortex lesions in the touchscreen TUNL task.
Bottom Line: The neural structures that support the retention of memories over time has been a subject of intense research in cognitive neuroscience.It remains unclear, however, to what extent these two processes can be neurally dissociated.When compared with previously published results, these data show that whereas the prefrontal cortex and hippocampus likely interact in the service of working memory across a delay, only the hippocampus and not the medial prefrontal cortex is essential for pattern separation.
Affiliation: University of Cambridge Department of Psychology, Downing Street, Cambridge, CB2 3EB, UK. firstname.lastname@example.orgShow MeSH
Related in: MedlinePlus
Mentions: Particularly striking were the clear contrasts – but also the similarities – between the pattern of impairment following mPFC lesions and that following hippocampal dysfunction. Both prefrontal cortex lesions and hippocampal lesions produced significant impairments in the presence of a 6 s delay (Fig. 9). However, whereas lesions of the hippocampus impaired pattern separation (as shown by impairments at small separations and not large ones), mPFC lesions in the present study had no effect on pattern separation at minimal delay, even when separations were made so small as to bring performance well down from ceiling. This pattern suggest that whereas both the hippocampus and mPFC are essential for retention of memories across a short delay, and likely functionally interact in this regard, only the hippocampus is necessary for spatial pattern separation. In addition, the finding of no impairment in difficult pattern separation conditions shows that PFC lesions do not simply produce impairments in any condition in which the task is made more difficult.
Affiliation: University of Cambridge Department of Psychology, Downing Street, Cambridge, CB2 3EB, UK. email@example.com