Study Description
There are many reports of improved precision of basic visual visuospatial perception in childhood, but it is unclear to which extent this depends on greater precision of information in the system, or more effecient read-out of this information by higher-order brain areas that form decisions and responses. The aim of this study was to investigate if spatial tuning functions of populations of neurons in visual cortex are adult-like or are still developing / becoming more precise from the age of 6 years onwards. 

Details on data collection and design: 

Sample:
We tested 13 children aged 6-9 years (mean age = 8.7 (SD=0.8)), 17 children aged 9-12 years (mean age = 11.4 (SD=0.7)), and 7 adults (mean age = 11.4 (SD=0.7)). These all had normal or corrected to normal vision, and no known neurological abnormalities. They were recruited via local data-bases of volunteers, so this was an opportunity sample.


Design and Procedure: 
We measured functional MRI BOLD responses whilst children and adults viewed a simultaneous ring and wedge-shaped checkerboard traversing the screen they were viewing in the scanner (~14 degrees eccentricity). We then fit the BOLD response in the visual cortex with pRF two different types of pRF models, a bivariate gaussian (mu and sigma), and a difference of Gaussian (mu (centre), sigma1 (surround), sigma2 (suppression)). We also computed for each voxel in visual cortex what the eccentricity and polar angle were. We used polar angle to manually delineate retinotopic regions of interest (V1, V2v & V2d, V3v, V3d, V3a, V4). We computed cortical magification factor for each voxel.

For details, please see: Dekker, T. M., Schwarzkopf, D. S., de Haas, B., Nardini, M., & Sereno, M. I. (2019). Population receptive field tuning properties of visual cortex during childhood. Developmental cognitive neuroscience, 100614.



Measures and preprocessing: 
Data were collected on a 1.5T Avanto scanner, and preprocessed using motion correction, alignment of functional to structural using SPM and Freesurfer, and surface reconstruction of structural scan using Freesurfer. Functional data were then sampled onto the surface using the Samsrf matlab Toolbox, and pRF models were fit using this same toolbox.

Again, please see: Dekker, T. M., Schwarzkopf, D. S., de Haas, B., Nardini, M., & Sereno, M. I. (2019). Population receptive field tuning properties of visual cortex during childhood. Developmental cognitive neuroscience, 100614.



EXPLANATION OF THE EXCEL DATA FILES

The excel file contains 3 sheets with results per individual from 3 different pRF analyses. All files contain:

subjectId = subject number
age = subject age un years
agegroup = age group the subject belongs to

All sheets contain measures of pRF model properties computed for brain regions within retinotopic areas representing different eccentricities. This was done by binning voxels by eccentricity in 14 eccentricity bins, (0.5-1.5, 1.5-2.5 etc.) and then computing the median of the pRF value of interest within these bins. Missing values mean that it was not possible to obtain a sufficiently large number of significant pRF fits to compute central tendencies.


Sheet 1 (sigma) contains the median pRF size (sigma) of the bivariate Gaussian model, within retinotopic region of interest, with voxels in these regions grouped into 14 eccentricity bins.

Sheet 2 (cmf) contains the average cortical magnification factor within retinotopic region of interest, with voxels in these regions grouped into 14 eccentricity bins.

Sheet 3 (DOG) contains the median best-fitting pRF parameters for the Difference of Gaussian model that was fit to BOLD response in each voxel within retinotopic region of interest, with voxels in these regions grouped into 14 eccentricity bins.