Читать книгу The Science of Reading - Группа авторов - Страница 29

Our conclusion on the contribution of neuroimaging results is brief: Their contribution so far to comprehension theory is limited, especially in the context of comprehension of texts longer than one or two sentences. Early neuroimaging studies identified brain regions associated with reading narrative texts (e.g., Xu et al., 2005; Yarkoni et al., 2008) and correlated brain activation with behavioral measures of comprehension – for example, detection of coherence breaks (e.g., Ferstl et al., 2005; Hasson et al., 2007) and inference generation (Kuperberg et al., 2006; Virtue et al., 2006). A general conclusion is that text comprehension, beyond sentence comprehension, involves an extension of the language network (Ferstl et al., 2008). This network includes the left lateralized language areas in the frontal and temporal lobes identified in sentence comprehension, plus extension to the anterior temporal pole, prefrontal area, and the right hemisphere. These additional areas are broadly associated with semantic processing, executive functioning and inferencing, and coherence building and non‐literal meaning, respectively (Ferstl et al., 2008).

More recently, research has sought to connect imaging results with other important issues in comprehension research – reading narrative versus expository texts (Aboud et al., 2019), local versus global comprehension (Egidi & Caramazza, 2013), and responses to differences in text coherence (Helder et al., 2017). Beyond identifying brain regions are proposals for how other brain networks interact with language areas during comprehension (Hagoort, 2019).

One reason for the limited contribution of imaging studies to cognitive explanations of comprehension is the low temporal resolution of the fMRI BOLD signal. In our streams metaphor, this signal shows the slower currents (and down‐stream results of the fast currents). Because it reflects the flow of oxygenated blood to brain areas, the BOLD signal develops slowly, over seconds, whereas incremental comprehension processes occur over milliseconds. Further, fMRI images provide only the strength of the correlation between the expected and observed ratios of oxygenated blood during a reading task. These factors limit the interpretations of the underlying processes of comprehension. Although this is also true for imaging studies of word identification, the results there show enough convergence to be connected to theory and behavioral results. A promising approach for comprehension is to connect the brain areas identified in fMRI to the interpretation of ERP components that reflect meaning and integration processes (Brouwer & Hoeks, 2013)