Archives

  • 2018-07
  • 2018-10
  • 2018-11
  • 2019-04
  • 2019-05
  • 2019-06
  • 2019-07
  • 2019-08
  • 2019-09
  • 2019-10
  • 2019-11
  • 2019-12
  • 2020-01
  • 2020-02
  • 2020-03
  • 2020-04
  • 2020-05
  • 2020-06
  • 2020-07
  • 2020-08
  • 2020-09
  • 2020-10
  • 2020-11
  • 2020-12
  • 2021-01
  • 2021-02
  • 2021-03
  • 2021-04
  • 2021-05
  • 2021-06
  • 2021-07
  • 2021-08
  • 2021-09
  • 2021-10
  • 2021-11
  • 2021-12
  • 2022-01
  • 2022-02
  • 2022-03
  • 2022-04
  • 2022-05
  • 2022-06
  • 2022-07
  • 2022-08
  • 2022-09
  • 2022-10
  • 2022-11
  • 2022-12
  • 2023-01
  • 2023-02
  • 2023-03
  • 2023-04
  • 2023-05
  • 2023-06
  • 2023-07
  • 2023-08
  • 2023-09
  • 2023-10
  • 2023-11
  • 2023-12
  • 2024-01
  • 2024-02
  • 2024-03
  • 2024-04
  • 2024-05
  • 2024-06
  • 2024-07
  • 2024-08
  • 2024-09
  • 2024-10
  • 2024-11
  • 2024-12

    • In addition to these findings in adults there is

    2018-11-01

    In addition to these findings in adults, there is emerging evidence from developmental fMRI studies demonstrating age-related hemispheric lateralization in the IPS. In a longitudinal fMRI study, Emerson and Cantlon (2014) recently demonstrated developmental differences in right and left IPS activation in children ranging from 4- to 9-years of age. More specifically, children were instructed to decide whether presented number pairs, consisting of dots and digits, were the same or different across these different notations. The authors were able to show that the Aminoallyl-UTP activation of the right IPS was significantly correlated over a 1–2 year period in young children, whereas the brain activation of the left IPS continued to be modulated over developmental time and as a function of children\'s numerical discrimination acuity. Together with the reported results of the presented work, the study by Emerson and Cantlon (2014) indicates an early and possibly stable activation of the right IPS, while protracted developmental changes in the representation of symbolic numerical magnitude occur in the left. In addition, the findings by Emerson and Cantlon (2014) indicate that age-related changes in the left IPS are associated with more accurate representations of symbolic numerical magnitude and that this refinement of representations is associated with numerical skills. This finding is largely in line with the result of the present work demonstrating an age-related change in the acuity of signal recovery in the left IPS over developmental time. Therefore, the age-dependent change observed in the left IPS may be related to ongoing refinement of symbolic numerical magnitude representation. This developmental pattern of IPS involvement provides increasing evidence for the hypothesis that brain activation of the left IPS is crucial for a mature system of numerical symbol processing (Ansari, 2007; Chochon et al., 1999; Dehaene and Cohen, 1995). The developmental changes in the left IPS demonstrated in the current study may reflect an experience-dependent process in which children gain a more refined understanding of the semantic information that is conveyed by numerical symbols. Experience dependent lateralization effects have also been observed in other culturally transmitted domains – such as reading (Dehaene and Cohen, 2011; Dehaene et al., 2010; Nuñez et al., 2011; Spironelli and Angrilli, 2009) – indicating that experience dependent specialization is common amongst culturally mediated domains. The acquisition of symbolic numerical magnitude knowledge may thereby go well beyond an initial mapping account between symbolic and non-symbolic representation (possibly mediated by the right hemisphere). Rather, it may encompass the integration of other non-magnitude related dimensions such as ordinality (i.e., the knowledge that number 5 comes before the number 6 but after the number 4) and language in order to construct fluent and efficient symbolic numerical knowledge (Lyons et al., 2012; Lyons and Beilock, 2011). There is increasing evidence that the semantics conveyed by numerical symbols (and therefore the numerical ratio effect) may contain information that go beyond a simple association between symbols and the non-symbolic numerical magnitude they refer to. For instance, there is emerging evidence that the sequential relationship between numbers (i.e., ordinal information between the symbols: 2 comes before 3 but after 1) is another critical dimension that is conveyed by numerical symbols (Lyons and Beilock, 2013; Lyons et al., 2014). As such, it can be argued that the developmental processes related to symbolic numerical representation may consist of a combination of different relevant dimensions. For instance, two recent published studies showed that mathematical achievement in grades 1 and 2 was best predicted by behavioural symbolic numerical magnitude discrimination abilities (Lyons et al., 2014; Vogel et al., 2015). In contrast, by grade 6, measurements of numerical order processing (i.e., the relationship between the numbers in the number sequence) systematically became the most important predictor of mathematical achievement in children (Lyons et al., 2014). As such, these data point towards a developmental crossover in the relative importance of numerical magnitude and numerical order processing in children and their relationship to mathematical proficiency. The differential engagement of the right and left IPS may be reflective of this development and may explain recent findings that demonstrated a significant relationship between individual differences in the children\'s activation of the IPS during symbolic number comparison tasks and their levels of mathematical achievement (Bugden et al., 2012). However, the precise nature of right and left IPS engagement and the mechanisms underlying developmental changes in the left IPS in the present work remain opaque; future research is required.