Prolonged rote learning produces delayed memory facilitation and metabolic changes in the hippocampus of the ageing human brain
1 School of Psychology & Trinity College Institute of Neuroscience, University of Dublin, Trinity College, Dublin 2, Ireland
2 Dept of Psychology, National University of Ireland, Maynooth, Co. Kildare, Ireland
3 School of Medicine & Medical Science, University College Dublin, Dublin 4, Ireland
4 Dept of Radiology & Diagnostic Imaging, Beaumont Hospital, Dublin 9, Ireland
5 St Patrick's Hospital, PO Box 136, James's St, Dublin 8, Ireland
BMC Neuroscience 2009, 10:136 doi:10.1186/1471-2202-10-136Published: 20 November 2009
Repeated rehearsal is one method by which verbal material may be transferred from short- to long-term memory. We hypothesised that extended engagement of memory structures through prolonged rehearsal would result in enhanced efficacy of recall and also of brain structures implicated in new learning. Twenty-four normal participants aged 55-70 (mean = 60.1) engaged in six weeks of rote learning, during which they learned 500 words per week every week (prose, poetry etc.). An extensive battery of memory tests was administered on three occasions, each six weeks apart. In addition, proton magnetic resonance spectroscopy (1H-MRS) was used to measure metabolite levels in seven voxels of interest (VOIs) (including hippocampus) before and after learning.
Results indicate a facilitation of new learning that was evident six weeks after rote learning ceased. This facilitation occurred for verbal/episodic material only, and was mirrored by a metabolic change in left posterior hippocampus, specifically an increase in NAA/(Cr+Cho) ratio.
Results suggest that repeated activation of memory structures facilitates anamnesis and may promote neuronal plasticity in the ageing brain, and that compliance is a key factor in such facilitation as the effect was confined to those who engaged fully with the training.