Developmental increases in effective connectivity to brain regions involved in phonological processing during tasks with orthographic demands

Abstract

Developmental differences (9-to 15-year-olds) in effective connectivity in left hemisphere regions were examined using dynamic causal modeling (DCM) of functional magnetic resonance imaging (fMRI) data. Children completed spelling tasks in the visual and auditory modalities in which they were asked to determine if two words were spelled the same from the first vowel onwards. Intrinsic (anatomical) connections were strongest from primary cortical regions to unimodal association areas -from Heschl's gyrus to superior temporal gyrus for the auditory spelling task and from calcarine to fusiform gyrus for the visual spelling task. The modulatory (experimental) effect for the visual spelling task from calcarine to superior temporal gyrus was stronger than all other effects from calcarine and this effect showed a developmental increase, suggesting automatic activation of phonology that increased with age. The modulatory effect from Heschl's gyrus to dorsal inferior frontal gyrus also showed a developmental increase, suggesting age-related increases in phonological segmentation in verbal working memory. All together, these results suggest that there are developmental increases in automatic access into brain regions involved in phonological processing in tasks that require orthographic processing.

The Dorsal Attention Network Reflects Both Encoding Load and Top–down Control during Working Memory

“…First, the manipulation of control was associated, specifically in the verbal modality, with neural patterns in a wide-spread, left-hemisphere dominant frontotemporal network, involving the inferior pFC, the supramarginal gyrus, and the temporo-occipital cortices. The regions of this network are known to support controlled phonological and orthographic segmentation and comparison processes (Deng, Chou, Ding, Peng, & Booth, 2011;Booth, Mehdiratta, Burman, & Bitan, 2008); these processes may have allowed participants, in the auditory-verbal high control condition, to segment the incoming speech stream and explicitly compare the segmented stimuli to the target stimulus category defined by both phonological and orthographic characteristics. This may also have included attempts at rehearsing the target stimuli in the high control condition (as each target stimulus is followed by a nontarget stimulus, which can be actively ignored, leaving some small room for verbal rehearsal); in the low control conditions, this strategy is indeed very unlikely as verbal rehearsal in standard running span conditions, which come closest to the low control trials used in this study, is known to be very difficult to implement and even worsens performance (Bhatarah, Ward, Smith, & Hayes, 2009;Hockey, 1973).…”

Effects of Training of Processing Speed on Neural Systems

“…While the left perisylvian's function is described above, the lingual gyrus is believed to play an important role in recognizing words (Kuriki et al, 1998). The lingual gyrus and the regions in the left perisylvian area strongly strengthen their functional coupling during visual spelling (Booth et al, 2008). The lingual gyrus is structurally connected with the lateral temporal regions by the inferior longitudinal fasciculus (Catani et al, 2003).…”

The timing of language learning shapes brain structure associated with articulation

“…The left putamen has been identified as a subcortical structure playing a key role in language production, especially in motor programming and articulatory coding (Booth et al 2008;Marchand et al 2008). Previous research has reported increased activation of the left putamen in late bilinguals during L2 speech production, an observation taken to reflect the complex articulatory demands imposed by speaking in a non-native language (Abutalebi et al 2013;Klein et al 2006;Frenck-Mestre et al 2005;Klein et al 1994Klein et al , 1995.…”