No evidence that working memory training alters gray matter structure: A MRI surface -based analysis

Abstract

Attempts to determine the cognitive benefits of adaptive working memory training in healthy adults has resulted in a polarized and stagnating field. Heterogeneous approaches and problematic methodological choices have contributed to the controversy. Structural neuroimaging has the potential to identify biological changes present after working memory training, which could go undetected by cognitive outcome tasks. In this study, 24 healthy community dwelling adults aged 18 – 40 years underwent structural magnetic resonance neuroimaging (MRI) before and after completing a 6-week n-back working memory training program. An active control group (n = 24) completed 6-weeks of processing speed training using the same computerized platform and neuroimaging protocol. Cortical surface area, thickness, and volume measurements were collected in a-priori regions of interest in the frontal and parietal lobes. Subcortical and total gray matter volumes were also measured. Group by time repeated measures Analyses of Variance (RM-ANOVAs) were conducted to identify changes in surface area, thickness, or volume measurements associated with training type over time. Null results were present across all neuroanatomical metrics after correction for multiple comparisons. Findings of this study, in concert with recently published investigations, support the idea that adaptive n-back working memory training is not an effective method for inducing neuroanatomical change. Further investigation into other forms of training may help advance the field.