Practice effects in healthy older adults: Implications for treatment-induced neuroplasticity in Aphasia.

In treating aphasic individuals with anomia, practice naming pictures leads to better performance as measured by accuracy and reaction time. The neurocognitive mechanisms supporting such improvements remain elusive, in part due to gaps in understanding the influence of practice on neurotypical older adults. The current study investigated the influence of practice naming one set of low frequency pictures of actions and objects in 18 healthy older adults, ten of whom were tested twice approximately one month apart. Both item and task practice effects were observed in improved accuracy and response latencies naming pictures in the scanner. This same facilitation effect was observed in neuroimaging results. For example, a significant main effect of practice was observed in bilateral precuneus and left inferior parietal lobule, characterized by greater activity for naming practiced vs. unpracticed pictures. This difference was significantly diminished in subsequent runs after exposure to unpracticed pictures. Whole brain analyses across two sessions showed that practice effects were specific to practice, i.e., there were not similar observable changes in contrasts examining actions vs. objects over time. These findings have important implications for understanding treatment-induced neuroplasticity in anomia treatment.