Enhanced functional connectivity and increased gray matter volume of insula related to action video game playing

Study at a glance

• Authors: Diankun Gong, Hui He, Dongbo Liu, Weiyi Ma, Li Dong, Cheng Luo, Dezhong Yao
• Year: 2015
• Journal: Scientific Reports
• DOI: 10.1038/srep09763
• N: 57
• Design: Cross-sectional expert/amateur comparison; resting-state fMRI functional connectivity (3T, 255 volumes) using Cauda et al.’s (2011) ten insular seed ROIs, plus FreeSurfer surface-based grey-matter-volume (GMV) analysis of insular subregions. 27 AVG experts (≥6 y, regional/national champions) vs 30 amateurs (<1 y).

Key findings

• AVG experts show higher functional connectivity between insular subregions than amateurs, in a pattern of anterior-posterior integration and left-lateralisation. Direct index of insular functional integration (FC between the averaged anterior and averaged posterior ROIs) is greater in experts bilaterally (left t(55)=2.93, right t(55)=2.73, p’s<0.009), but only the LEFT integration correlated with weekly playing time (AT; r=0.68, p<0.001) — the correlational hook for an experience-driven rather than pre-existing difference.
• Increased GMV in the LEFT insula in experts, localized to the short insular gyri, long insular gyrus and central sulcus. GMV of the left long insular gyrus + central sulcus (a region near the anterior/posterior transitional zone) correlated with insular functional integration (r=0.47, p=0.02) and with AT (r=0.56, p=0.004); no significant correlations in the amateur group.
• Replicates Cauda et al. (2011) in the amateurs: anterior ROIs (1,2,4,5,8) recover a bilateral attentive ‘A-network’ (superior/middle/inferior frontal gyri, temporoparietal junction, ACC, superior temporal, putamen); posterior ROIs (3,7,10) recover a sensorimotor ‘P-network’ (pre/postcentral gyri, SMA, superior/middle temporal); ROIs 6 and 9 are transitional — the same ventral-anterior/dorsal-posterior functional axis, here used as a fixed template rather than rederived.
• The novel plasticity claim is a cross-network rewiring: in experts the POSTERIOR (sensorimotor) ROIs became functionally linked to the bilateral middle frontal gyrus (MFG) — a canonical A-network node — whereas in amateurs the MFG links to anterior ROIs. Read as enhanced functional integration between the attentional (A) and sensorimotor (P) networks, interpreted via shortened path length between MFG and sensorimotor cortex in experts.
• Interpretation: long-term action-video-game playing is associated with experience-dependent structural (GMV) and functional (FC) neuroplasticity of the insula, predominantly the left, enhancing integration of its attentional and sensorimotor subregions and networks. A longitudinal causal study is stated to be underway.

Limitations

• Cross-sectional expert-vs-amateur design — it cannot establish that AVG playing CAUSED the insular differences rather than pre-existing insular structure selecting who becomes an expert; the AT correlations are the only lever toward an experience account, and they are correlational within the expert group (the authors concede this and report a longitudinal study in progress).
• Not an interoception study. The insula is treated purely as an attentional/sensorimotor integration hub (following Cauda’s A/P network labels); no interoceptive measure, task, or physiological recording is taken, and ‘the insula’s function’ is imported wholesale from Cauda et al. rather than probed. Its relevance here is as experience-dependent plasticity of the same anterior/posterior functional axis the wiki’s insula page assumes, and as a downstream use of that parcellation.
• Groups differ on more than expertise: weekly playing time and game type differed significantly (used to verify group membership), and the confound-matching (Raven’s, exercise, onset age) leaves lifestyle differences uncontrolled. The left-lateralisation is asserted but the design cannot test a laterality hypothesis.
• The cross-network MFG↔posterior-insula finding — the paper’s distinctive result — rests on a spatial-consistency ‘probability network’ analysis and a path-length argument, not on a direct FC contrast with an effect size; the MFG’s own network membership (attentional vs control) is acknowledged to be ambiguous.
• GMV via FreeSurfer surface reconstruction (aparc.a2009s parcellation), 3T; correlational resting-state FC inherits the standing non-directional, motion-sensitive caveats of the method.

Connections

• Methods: Resting-state functional connectivity
• Concepts: Insular cortex, Salience network
• Debates: Is interoception domain-general or organ-specific?
• Related studies: Cauda et al. (2011), Deen et al. (2011), Chang et al. (2013), Farb et al. (2007), Farb et al. (2013)

A downstream application of the wiki’s insula-parcellation thread, and its clearest single demonstration that the insula’s anterior/posterior functional organization is experience-dependent rather than fixed. Gong et al. take Cauda et al.’s (2011) ten insular seed ROIs and their anterior-attentive (“A-network”) / posterior-sensorimotor (“P-network”) scheme as a template, then ask whether years of action-video-game (AVG) playing — a regime that demands sustained attention plus rapid hand-eye sensorimotor coordination (~150 keyboard/mouse responses per minute) — leaves a mark on it. Comparing 27 AVG experts (regional/national champions, ≥6 years) against 30 amateurs, they find higher FC between insular subregions in experts, increased grey-matter volume in the left insula, and a rewiring in which the posterior sensorimotor insula becomes coupled to a frontal attentional node.

Why it is filed here despite not being an interoception study

The paper never measures interoception, takes no physiological recording, and treats the insula strictly as an attention/sensorimotor hub — its account of “what the insula does” is imported from Cauda and the attentional-network literature, not tested. It earns a page for two narrow reasons:

• It is a plasticity result on the exact functional axis the wiki’s insula page assumes. Most of the Insular cortex evidence is anatomical, phylogenetic, or cross-sectional-correlational; the structure’s anterior→posterior gradient is usually stated as given. Gong et al. show the functional integration between those poles, and the grey matter near their transitional seam, scales with a behavioural regime — the closest thing the wiki holds to “the insular parcellation can be moved by experience,” alongside Farb et al.’s (2007) training-induced re-routing of insular connectivity and the GMV-from-training literature (Draganski, Boyke) it cites.
• It is a real-world use of the Cauda ROI scheme. The amateurs reproduce Cauda’s A-/P-network split from the same ten ROIs, which is a small independent replication of that parcellation in a fresh 3T sample — the anterior ROIs (1,2,4,5,8) recovering the attentive network, posterior ROIs (3,7,10) the sensorimotor one, ROIs 6/9 transitional.

Read against Is interoception domain-general or organ-specific?, the paper is a data point for the deflationary side: here the insula is a generic attention/sensorimotor integrator with no interoceptive content invoked at all, and the account works. That is the same “the anterior insula is not an area of pure body awareness” caution Farb (2013) and Haruki & Ogawa (2023) reach from inside the interoception literature — Gong et al. reach it by never entering it.

What was found

• Functional integration up, left more than right. A dedicated index — FC between the averaged anterior and averaged posterior insular ROIs — was greater in experts bilaterally (left t=2.93, right t=2.73), but only the left integration correlated with average weekly playing time (AT; r=0.68), which is what lets the authors argue for an experience effect rather than a static group difference.
• Grey matter up in the left insula. Increased GMV in the left short insular gyri, long insular gyrus and central sulcus. The long-gyrus/central-sulcus increase — sitting near the anterior/posterior transitional subregion — correlated with both the functional-integration index (r=0.47) and playing time (r=0.56), the paper’s structural-functional bridge: more play → more grey matter at the seam → more integration across it. No such correlations in amateurs.
• A cross-network rewiring. The distinctive claim. In amateurs the bilateral MFG (an attentive-network node) links to anterior insular ROIs, as expected. In experts the MFG instead links to the posterior (sensorimotor) ROIs — read as the attentional and sensorimotor networks becoming integrated, with a shorter graph path between MFG and sensorimotor cortex in experts. This is the mechanism the paper proposes for the behavioural profile (attention essential for sensorimotor performance).

The load-bearing caveat: cross-sectional, so causation is assumed not shown

Everything rests on an expert-vs-amateur contrast, which cannot separate “AVG playing sculpted the insula” from “people with this insula become AVG champions.” The AT correlations inside the expert group are the only evidence tilting toward experience, and they are still correlational. The authors are candid about this and state a longitudinal training study is underway — the wiki holds no follow-up. Treat the plasticity reading as the authors’ favoured interpretation of a correlational design, not an established causal effect. See Resting-state functional connectivity for the standing method caveats (non-directional FC, motion sensitivity), which apply on top.