Abstract
While a growing body of evidence suggests the age-associated reduction of global and regional thickness in the brain (eg. Lemaitre et al., 2010), it is not completely understood how aging affects the structure in the early visual area. Here, we tested whether aging affects surface size and/or thickness in the early visual areas, and if so, whether the cortical size and/or thickness in the early visual areas is correlated with performance on visual tasks with older people. We conducted a standard retinotopic mapping by 3T MRI in older (n=15, 65-86 yr) and younger participants (n=9, 19-28 yr) individually to localize V1, V2 and V3 in a flattened format of the cortical surface. Then, we measured the areal cortical surface size as well as the thickness in V1, V2 and V3 in each hemisphere. Moreover, we conducted 2 types of visual tasks with older participants: the texture discrimination task (Karni and Sagi, 1991), one of the standard visual perceptual learning tasks, and the useful field of view test (Roenker et al. 2003), a standard measure of attentional processing in older people. We found that the areal surface size in V1, V2, and V3 in the older participants was significantly smaller in comparison with the younger participants. In contrast, the cortical thickness did not display any significant age-related changes. Importantly, only the surface size of V3 was significantly correlated with the amount of improvement in the perceptual learning task, but not in the attention task, in the older participants: The larger size of V3 is associated with higher improvement after the 3-day training. These results clearly demonstrate the age-associated reduction in the early visual cortical surface space but not thickness, and further suggest that V3 area may play an important role in visual plasticity in older people.
Meeting abstract presented at VSS 2012