Cognitive development attenuates audiovisual distraction and promotes the selection of task-relevant perceptual saliency during visual search on complex scenes

Searching for a target while avoiding distraction is a core function of selective attention involving both voluntary and reflexive mechanisms. Here, for the first time, we investigated the development of the interplay between voluntary and reflexive mechanisms of selective attention from childhood to early adulthood. We asked 6-, 10-, and 20-year-old participants to search for a target presented in one hemifield of a complex scene, preceded by a task-irrelevant auditory cue on either the target side (valid), the opposite side (invalid), or both sides (neutral). For each scene we computed the number of salient locations (NSL) and the target saliency (TgS). All age groups showed comparable orienting effects (\u201cvalid minus neutral\u201d trials), indicating a similar capture of spatial attention by valid cues which was independent of age. However, only adults demonstrated a suppression of the reorienting effect (\u201cinvalid minus neutral\u201d trials), indicating late developments in the reallocation of spatial attention toward a target following auditory distraction. The searching performance of the children (both 6- and 10-year-olds), but not of the adults, was predicted by the NSL, indicating an attraction of processing resources to salient but task-irrelevant locations in childhood; conversely, only adults showed greater performance with increased TgS in valid trials, indicating late development in the use of task-related saliency. These findings highlight qualitatively different mechanisms of selective attention operating at different ages, demonstrating important developmental changes in the interplay between voluntary and reflexive mechanisms of selective attention during visual search in complex scenes

Enhanced brain activity associated with memory access in highly superior autobiographical memory

Brain systems underlying human memory function have been classically investigated studying patients with selective memory impairments. The discovery of rare individuals who have highly superior autobiographical memory (HSAM) provides, instead, an opportunity to investigate the brain systems underlying enhanced memory. Here, we carried out an fMRI investigation of a group of subjects identified as having HSAM. During fMRI scanning, eight subjects with HSAM and 21 control subjects were asked to retrieve autobiographical memories (AMs) as well as non-AMs (e.g., examples of animals). Subjects were instructed to signal the "access" to an AM by a key press and to continue "reliving" it immediately after. Compared with controls, individuals with HSAM provided a richer AM recollection and were faster in accessing AMs. The access to AMs was associated with enhanced prefrontal/hippocampal functional connectivity. AM access also induced increased activity in the left temporoparietal junction and enhanced functional coupling with sensory cortices in subjects with HSAM compared with controls. In contrast, subjects with HSAM did not differ from controls in functional activity during the reliving phase. These findings, based on fMRI assessment, provide evidence of interaction of brain systems engaged in memory retrieval and suggest that enhanced activity of these systems is selectively involved in enabling more efficient access to past experiences in HSAM