Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Meta-Analysis
. 2024 Sep;34(3):721-737.
doi: 10.1007/s11065-023-09609-z. Epub 2023 Aug 18.

Gradient Organization of Space, Time, and Numbers in the Brain: A Meta-analysis of Neuroimaging Studies

Giorgia Cona  1   2   3 , Martin Wiener  4 , Francesco Allegrini  5 , Cristina Scarpazza  5   6
Affiliations
Meta-Analysis

Gradient Organization of Space, Time, and Numbers in the Brain: A Meta-analysis of Neuroimaging Studies

Giorgia Cona et al. Neuropsychol Rev. 2024 Sep.

Abstract

In this study, we ran a meta-analysis of neuroimaging studies to pinpoint the neural regions that are commonly activated across space, time, and numerosity, and we tested the existence of gradient transitions among these magnitude representations in the brain. Following PRISMA guidelines, we included in the meta-analysis 112 experiments (for space domain), 114 experiments (time domain), and 115 experiments (numerosity domain), and we used the activation likelihood estimation method. We found a system of brain regions that was commonly recruited in all the three magnitudes, which included bilateral insula, the supplementary motor area (SMA), the right inferior frontal gyrus, and bilateral intraparietal sulci. Gradiental transitions between different magnitudes were found along all these regions but insulae, with space and numbers leading to gradients mainly over parietal regions (and SMA) whereas time and numbers mainly over frontal regions. These findings provide evidence for the GradiATOM theory (Gradient Theory of Magnitude), suggesting that spatial proximity given by overlapping activations and gradients is a key aspect for efficient interactions and integrations among magnitudes.

Keywords: Activation likelihood estimation; Gradients; Magnitudes; Meta-analysis; Neuroimaging; Numbers; Spatial; Time.

PubMed Disclaimer

Conflict of interest statement

The authors declare no competing interests exist.

Figures

Fig. 1
Fig. 1
Significant convergent activations in studies on numbers processing (A), space processing (B), and time processing (C). Color bars indicate the ALE values for each voxel above the threshold (where yellow indicates the most significant ALE values). Numbers indicate the z coordinate for each section. Image created using MRIcro
Fig. 2
Fig. 2
Pairwise direct comparison between numbers, space, and time. To simplify the interpretation of ALE contrast images, they are converted to z scores to show their significance instead of a direct ALE subtraction. Color bars indicate the z scores, where yellow indicates the higher z scores. Numbers indicate the z coordinate for each section. Image created using MRIcro
Fig. 3
Fig. 3
Regions of overlap between numbers, space and time. SMA, supplementary motor area; rIFG, right inferior frontal gyrus; IPL, inferior parietal lobule. For each section, the correspondent coordinate has been reported. Image created using MRIcro
Fig. 4
Fig. 4
Gradient analysis. Surface visualization of the overlap between space and numbers (left panel) and time and numbers (right panel) meta-analyses. ALE values for space and time were set to negative scores and added to ALE values from the number meta-analysis, effectively subtracting one from the other
Fig. 5
Fig. 5
Gradient plots and stability. Plots of gradients across seven regions within the SMA, L/R IFG, L/R insula, and L/R IPL. Each plot displays the gradients observed for both time-number (blue trace) and space-number (green trace) contrasts, with greater number ALE scores always plotted as positive. Red and orange lines display the mean of the null distribution for time-number and space-number contrasts, respectively. Shaded regions represent the standard deviation of each distribution
See this image and copyright information in PMC

References

    1. Albertini, D., Gerbella, M., Lanzilotto, M., Livi, A., Maranesi, M., Ferroni, C. G., & Bonini, L. (2020). Connectional gradients underlie functional transitions in monkey pre-supplementary motor area. Progress in Neurobiology, 184, 101699. 10.1016/j.pneurobio.2019.101699 - PubMed
    1. Anderson, M. L. (2010). Neural reuse: A fundamental organizational principle of the brain. The Behavioral and Brain Sciences,33(4), 245–313. 10.1017/S0140525X10000853 - PubMed
    1. Anderson, M. L. (2014). Complex function in the dynamic brain: Comment on “Understanding brain networks and brain organization” by Luiz Pessoa. Physics of Life Reviews,11(3), 436–437. 10.1016/j.plrev.2014.06.017 - PubMed
    1. Arsalidou, M., & Taylor, M. J. (2011). Is 2+2=4? Meta-analyses of brain areas needed for numbers and calculations. NeuroImage,54(3), 2382–2393. 10.1016/j.neuroimage.2010.10.009 - PubMed
    1. Behrens, T. E., Fox, P., Laird, A., & Smith, S. M. (2013). What is the most interesting part of the brain? Trends in Cognitive Sciences,17(1), 2–4. 10.1016/j.tics.2012.10.010 - PMC - PubMed

LinkOut - more resources