Flexible allocation of attention in time or space across the life span: Theta and alpha oscillatory signatures of age-related decline and compensation as revealed by MEG

In our recent behavioural research (Callaghan et al., 2017) we reported age-related changes in the speed of switching between temporal and spatial attention. Using magnetoencephalography (MEG), we now compared the neural signatures between three age groups (19-30, 40-49 and 60+ years) and found differences in task-related modulation and cortical localisation of alpha and theta oscillations as well as in functional network connectivity. Efficient (fast) switching between the temporal and spatial attention tasks in the youngest group was reflected by parietal theta effects that were absent in the older groups. Difficulties in refocusing attention in the older and middle-aged adults (slowed response times) were accompanied by reduced theta power modulation in occipital and cerebellar regions. Older and middle-aged adults seem to compensate for this posterior theta deficit with increased recruitment of frontal (both groups) and temporal (older group) areas, possibly reflecting a greater dependence on top-down attentional control. Importantly, rather than theta oscillatory connectivity becoming weaker with age due to increased neural noise, both older age groups displayed stronger and more widely distributed connectivity. However, d...Continue Reading