An Updated Survey on Statistical Thresholding and Sample Size of fMRI Studies

Seuils statistiques et tailles des échantillons des études en IRMf: une nouvelle recension de la littérature


Yeung, A. W. K. (2018). An Updated Survey on Statistical Thresholding and Sample Size of fMRI Studies. Frontiers in Human Neuroscience12, 16.

DOI: 10.3389/fnhum.2018.00016


Background: Since the early 2010s, the neuroimaging field has paid more attention to the issue of false positives. Several journals have issued guidelines regarding statistical thresholds. Three papers have reported the statistical analysis of the thresholds used in fMRI literature, but they were published at least 3 years ago and surveyed papers published during 2007–2012. This study revisited this topic to evaluate the changes in this field.

Methods: The PubMed database was searched to identify the task-based (not resting-state) fMRI papers published in 2017 and record their sample sizes, inferential methods (e.g., voxelwise or clusterwise), theoretical methods (e.g., parametric or non-parametric), significance level, cluster-defining primary threshold (CDT), volume of analysis (whole brain or region of interest) and software used.

Results: The majority (95.6%) of the 388 analyzed articles reported statistics corrected for multiple comparisons. A large proportion (69.6%) of the 388 articles reported main results by clusterwise inference. The analyzed articles mostly used software Statistical Parametric Mapping (SPM), Analysis of Functional NeuroImages (AFNI), or FMRIB Software Library (FSL) to conduct statistical analysis. There were 70.9%, 37.6%, and 23.1% of SPM, AFNI, and FSL studies, respectively, that used a CDT of p ≤ 0.001. The statistical sample size across the articles ranged between 7 and 1,299 with a median of 33. Sample size did not significantly correlate with the level of statistical threshold.

Conclusion: There were still around 53% (142/270) studies using clusterwise inference that chose a more liberal CDT than p = 0.001 (n = 121) or did not report their CDT (n = 21), down from around 61% reported by Woo et al. (2014). For FSL studies, it seemed that the CDT practice had no improvement since the survey by Woo et al. (2014). A few studies chose unconventional CDT such as p = 0.0125 or 0.004. Such practice might create an impression that the threshold alterations were attempted to show “desired” clusters. The median sample size used in the analyzed articles was similar to those reported in previous surveys. In conclusion, there seemed to be no change in the statistical practice compared to the early 2010s.

Longitudinal brain development of numerical skills in typically developing children and children with developmental dyscalculia

Développement cérébral longitudinal des compétences numériques chez les enfants au développement "typique" et chez les enfants atteints de dyscalculie développementale


McCaskey, U., von Aster, M., Maurer, U., Martin, E., O'Gorman Tuura, R., & Kucian, K. (2017). Longitudinal brain development of numerical skills in typically developing children and children with developmental dyscalculia. Frontiers in Human Neuroscience11, 629.

DOI: 10.3389/fnhum.2017.00629


Developmental dyscalculia (DD) is a learning disability affecting the acquisition of numerical-arithmetical skills. Studies report persistent deficits in number processing and aberrant functional activation of the fronto-parietal numerical network in DD. However, the neural development of numerical abilities has been scarcely investigated. The present paper provides a first attempt to investigate behavioral and neural trajectories of numerical abilities longitudinally in typically developing (TD) and DD children. During a study period of 4 years, 28 children (8–11 years) were evaluated twice by means of neuropsychological tests and a numerical order fMRI paradigm. Over time, TD children improved in numerical abilities and showed a consistent and well-developed fronto-parietal network. In contrast, DD children revealed persistent deficits in number processing and arithmetic. Brain imaging results of the DD group showed an age-related activation increase in parietal regions (intraparietal sulcus), pointing to a delayed development of number processing areas. Besides, an activation increase in frontal areas was observed over time, indicating the use of compensatory mechanisms. In conclusion, results suggest a continuation in neural development of number representation in DD, whereas the neural network for simple ordinal number estimation seems to be stable or show only subtle changes in TD children over time.

Brain development, Child, Developmental dyscalculia, Longitudinal, Number processing

Structural plasticity of the social brain: Differential change after socio-affective and cognitive mental training

Plasticité structurelle du "cerveau social": changements suite à un entrainement socio-affectif et cognitif


Valk, S. L., Bernhardt, B. C., Trautwein, F. M., Böckler, A., Kanske, P., Guizard, N., ... & Singer, T. (2017). Structural plasticity of the social brain: Differential change after socio-affective and cognitive mental training. Science Advances3(10), e1700489.

DOI: 10.1126/sciadv.1700489


Although neuroscientific research has revealed experience-dependent brain changes across the life span in sensory, motor, and cognitive domains, plasticity relating to social capacities remains largely unknown. To investigate whether the targeted mental training of different cognitive and social skills can induce specific changes in brain morphology, we collected longitudinal magnetic resonance imaging (MRI) data throughout a 9-month mental training intervention from a large sample of adults between 20 and 55 years of age. By means of various daily mental exercises and weekly instructed group sessions, training protocols specifically addressed three functional domains: (i) mindfulness-based attention and interoception, (ii) socio-affective skills (compassion, dealing with difficult emotions, and prosocial motivation), and (iii) socio-cognitive skills (cognitive perspective-taking on self and others and metacognition). MRI-based cortical thickness analyses, contrasting the different training modules against each other, indicated spatially diverging changes in cortical morphology. Training of present-moment focused attention mostly led to increases in cortical thickness in prefrontal regions, socio-affective training induced plasticity in frontoinsular regions, and socio-cognitive training included change in inferior frontal and lateral temporal cortices. Module-specific structural brain changes correlated with training-induced behavioral improvements in the same individuals in domain-specific measures of attention, compassion, and cognitive perspective-taking, respectively, and overlapped with task-relevant functional networks. Our longitudinal findings indicate structural plasticity in well-known socio-affective and socio-cognitive brain networks in healthy adults based on targeted short daily mental practices. These findings could promote the development of evidence-based mental training interventions in clinical, educational, and corporate settings aimed at cultivating social intelligence, prosocial motivation, and cooperation.

Video gamers have an advantage in learning / Jouer à des jeux vidéos favoriserait l'apprentissage

(see related scientific article below / voir l'article scientifique source plus bas)

Science Daily
Click here to access outreach article / Cliquer ici pour accéder à cet article de vulgarisation

Neuropsychologists let video gamers compete against non-gamers in a learning competition. During the test, the video gamers performed significantly better and showed an increased brain activity in the brain areas that are relevant for learning.

Dans une tâche compétitive d'apprentissage, des neuropsychologues ont confronté des adeptes de jeux vidéos à des "non joueurs". Pendant cette tâche, les adeptes de jeux vidéos ont significativement mieux performé et ont fait preuve d'une activité cérébrale plus grande dans les régions associées à l'apprentissage. 


Games people play: How video games improve probabilistic learning

Schenk, S., Lech, R. K., & Suchan, B. (2017). Games people play: How video games improve probabilistic learning. Behavioural Brain Research335, 208-214.

DOI: 10.1016/j.bbr.2017.08.027


Recent research suggests that video game playing is associated with many cognitive benefits. However, little is known about the neural mechanisms mediating such effects, especially with regard to probabilistic categorization learning, which is a widely unexplored area in gaming research. Therefore, the present study aimed to investigate the neural correlates of probabilistic classification learning in video gamers in comparison to non-gamers. Subjects were scanned in a 3 T magnetic resonance imaging (MRI) scanner while performing a modified version of the weather prediction task. Behavioral data yielded evidence for better categorization performance of video gamers, particularly under conditions characterized by stronger uncertainty. Furthermore, a post-experimental questionnaire showed that video gamers had acquired higher declarative knowledge about the card combinations and the related weather outcomes. Functional imaging data revealed for video gamers stronger activation clusters in the hippocampus, the precuneus, the cingulate gyrus and the middle temporal gyrus as well as in occipital visual areas and in areas related to attentional processes. All these areas are connected with each other and represent critical nodes for semantic memory, visual imagery and cognitive control. Apart from this, and in line with previous studies, both groups showed activation in brain areas that are related to attention and executive functions as well as in the basal ganglia and in memory-associated regions of the medial temporal lobe. These results suggest that playing video games might enhance the usage of declarative knowledge as well as hippocampal involvement and enhances overall learning performance during probabilistic learning. In contrast to non-gamers, video gamers showed better categorization performance, independently of the uncertainty of the condition.

Probabilistic categorization learning; Video games; Hippocampus; Enrichment of environment

The role of mathematical anxiety and working memory on the performance of different types of arithmetic tasks

Le rôle de l'anxiété et de la mémoire de travail sur la performance dans différentes tâches mathématiques


Ashkenazi, S., & Danan, Y. (2017). The role of mathematical anxiety and working memory on the performance of different types of arithmetic tasks. Trends in Neuroscience and Education7, 1-10.

DOI: 10.1016/j.tine.2017.05.001


Goal of the current study was to compare the respective roles of domain general cognitive skills with domain specific quantitative understanding, as well as the effect of math anxiety, on the performance of different types of arithmetic tasks. Fifty-eight adults performed a battery of tests. We found dissociations between domain general abilities that supported verbally or spatially mediated arithmetic tasks. The verbally mediated tasks were supported by the verbal central executive component of working memory, while the spatially mediated task, number line knowledge, was supported by the spatial central executive component of working memory. Different tasks had differential relationships with math anxiety: math anxiety effected school-like math tasks more than verbally mediated tasks and number line task. Math anxiety was negatively influenced by the spatial central executive component of working memory, indicating that spatial working memory can be a source of vulnerability to math anxiety.

Working memory; Mathematical anxiety; Approximate number sense; Arithmetic; Verbal code of number