Cortical thickness and spatial frequency processing during natural scenes perception in children

International audience; INTRODUCTIONRecent models of visual perception suggested that scene recognition is processed in terms of spatial frequencies: in adults, low spatial frequencies (LSF) rapidly reach high-order cortical areas to allow initial scene recognition and high spatial frequencies (HSF) subsequently carry fine details analysis (Kauffmann, 2014). Paradigms using compound stimuli (large global forms, supposed to convey HSF, composed of arrangements of small local forms, supposed to convey HSF) had indicated an evolution from a local (HSF) preference in young children (Poirel, 2008) evolving toward a global (LSF) preference, from 6 years of age until the end of adolescence (Mondloch, 2003). The present MRI study investigated for the first time the relationship between cortical thickness and behavioral performances to LSF/HSF during this childhood transitional period. METHODSSixteen children (M=10 years, SD=7 months, 6 boys) and 16 adults (M=30 years, SD=5 years, 9 boys) were presented with 80 pictures of natural scenes filtered either in LSF or in HSF (Fig1). Each scene was presented during 40ms and participants had to indicate as rapidly as possible whether the scene was outdoor or indoor. Reaction times were recorded. Participants were scanned with a 3-Tesla MRI scanner (T1-weighted, FOV: 256mm; slice thickness: 1.33 mm; 128 slices; matrix size 192×192 voxels; 5min7s duration). Mean cortical thickness values were extracted with Freesurfer software using the Destrieux Atlas (2010). For each group, regression analyses were carried to investigate the relationship between cortical thickness and LSF/HSF reaction times (RTs). All results reported are statistically significant at 0.05.RESULTSBehavioral data indicated that adults showed faster RTs than children (495±12ms and 867±34ms respectively, p