Repeated cognitive excercise impacts on behavioural performance and neural cell health/viability. It is one method by which verbal material is transferred from short to long-term memory stores. Proton magnetic resonance spectroscopy (¹H-MRS) has shown age-related alterations in neural N-acetylaspartate, creatine and choline which are related to memory performance and cell health. The aim of this study is to determine if prolonged activation of memory structures facilitates new learning of verbal material, improved recall, and leads to post-learning neurometabolic changes in memory-related brain structures on MRS.

Twenty-four healthy paticipants [55-70yrs; Mean=60.1] were randomly allocated to two learning groups. Groups were matched for gender, age, intelligence (National Adult Reading Test) and absentmindedness (Cognitive Failures Questionnaire). Groups engaged in 6 weeks of intensive rote learning, during which they learned 500 words every week. Using a crossover design, Group A spent 6 weeks learning while the others rested; after 6 weeks, the groups reversed. An extensive battery of learning and memory tests was administered on four occassions, each 6 weeks apart. In addition, MRS was used to measure metabolite levels in seven 2cm³ voxels before and after learning.

A facilitation of new learning was evident 6 weeks after rote learning ceased for Group A. This occured for verbal/episodic material only, and was mirrored by metabolic changes in left posterior hippocampus. Significant correlations between behavioural measures and MRS clustered in two regions, left pre-frontal cortex and left hippocampus. No coherent pattern of behavioural or metabolic change was evident for Group B, in which compliance was low.

With high compliance, a prolonged period of rote learning can lead to improvements in verbal/episodic memory which emerge following learning cessation. This appears to be associated with metabolic changes in the left posterior hippocampus, which may reveal the health implications for key brain structures of repetitive activation and regular usage.

MRS may be used to identify the key metabolic changes associated with neural cell health.