Abstract
Perceptual Learning (PL) and the underlying neural plasticity have been mostly studied with younger adults. For example, with younger adults,BOLD activity changes were observed only in the trained region of V1 due to PL (Yotsumoto, Watanabe and Sasaki, 2008). Recent research has found evidence of PL for older subjects (Ni, Watanabe and Andersen, 2007) Here, we examined PL examined the underlying neural mechanisms of PL in older subjects by measuring BOLD responses.
Older adults, aged 65–75 years, underwent three behavioral training sessions of a texture discrimination task (TDT) (Karni and Sagi, 1992). Each session lasted about 45 minutes and was conducted on three separate days. They also participated in two fMRI sessions before and after the series of training sessions. PL training occurred in one quadrant of the visual field. In the fMRI sessions the trained and a non-trained quadrant were tested and BOLD activities in respective regions of cortical areas were compared.
Results showed (1) that TDT performance with older subjects improved after training and (2) that BOLD activity only in the trained region/side of each V1, V2, V3 and the dorsolateral prefrontal cortex was significantly larger than in an untrained region/side.
These results indicate that in contrast to PL with younger adults in which only V1 was activated, multiple areas are involved in PL with older individuals. These results suggest that as aging occurs recruitment of multiple new areas may be needed to compensate for less plasticity in V1. In addition, neural recruitment occurs only in the trained region of the areas critical to perform the task.
NIH AG13419-06, EY18334-01, R21 EY018925, R01 EY15980-04A2, NSF BCS-0549036, HFSP RGP 18/2004