Publications from 2007
Bitan T, Burman DD, Chou TL, Lu D, Cone NE, Cao F, Bigio JD & Booth JR (2007) The interaction between orthographic and phonological information in children: an fMRI study. Human Brain Mapping, 28, 880-891. [pdf]
We examined the neural representations of orthographic and phonological processing in children, while manipulating the consistency between orthographic and phonological information. Participants, ages 9-15, were scanned while performing rhyming and spelling judgments on pairs of visually presented words. The orthographic and phonological similarity between words in the pair was independently manipulated, resulting in four conditions. In the non-conflicting conditions, both orthography and phonology of the words were either (1) similar (lime-dime) or (2) different (staff-gain). In conflicting conditions, words had (3) similar phonology and different orthography (jazz-has) or (4) different phonology and similar orthography (pint-mint). The comparison between tasks resulted in greater activation for the rhyming task in bilateral inferior frontal gyri (BA 45/47), and greater activation for the spelling task in bilateral inferior/superior parietal lobules (BA 40/7), suggesting greater involvement of phonological and semantic processing in the rhyming task, and non-linguistic spatial processing in the spelling task. Conflicting conditions were more difficult in both tasks and resulted in greater activation in the above regions. The results suggest that when children encounter inconsistency between orthographic and phonological information they show greater engagement of both orthographic and phonological processing.
Bitan T, Cheon J, Lu D, Burman DD, Gitelman D, Mesulam MM & Booth JR (2007). Developmental changes in activation and connectivity in phonological processing. Neuroimage, 38, 564-575. [pdf]
The current study examined developmental changes in activation and effective connectivity among brain regions during a phonological processing task, using fMRI. Participants, ages 9-15, were scanned while performing rhyming judgments on pairs of visually presented words. The orthographic and phonological similarity between words in the pair was independently manipulated, so that rhyming judgment could not be based on orthographic similarity. Our results show a developmental increase in activation in the dorsal part of left inferior frontal gyrus (IFG), accompanied by a decrease in the dorsal part of left superior temporal gyrus (STG). The coupling of dorsal IFG with other selected brain regions involved in the phonological decision increased with age, while the coupling of STG decreased with age. These results suggest that during development there is a shift from reliance on sensory auditory representations to reliance on phonological segmentation and covert articulation for performing rhyming judgment on visually presented words. In addition, we found a developmental increase in activation in left posterior parietal cortex that was not accompanied by a change in its connectivity with the other regions. These results suggest that maturational changes within a cortical region are not necessarily accompanied by an increase in its interactions with other regions and its contribution to the task. Our results are consistent with the idea that there is reduced reliance on primary sensory processes as task-relevant processes mature and become more efficient during development.
Booth JR, Cho S, Burman DD & Bitan T (2007). The neural correlates of mapping from phonology to orthography in children performing an auditory spelling task. Developmental Science, 10, 441-451. [pdf]
Age-related differences (9- to 15-year-olds) in the neural correlates of mapping from phonology to orthography were examined with functional magnetic resonance imaging (fMRI). Participants were asked to determine if two spoken words had the same spelling for the rime (corresponding letters after the first consonant or consonant cluster). Some of the word pairs had conflicting orthography and phonology (e.g. jazz-has, pint-mint) whereas other pairs had non-conflicting information (e.g. press-list, gate-hate). There were age-related increases in activation for lexical processing (across conflicting and non-conflicting conditions) in left inferior parietal lobule, suggesting that older children have a more elaborated system for mapping between phonology and orthography that includes connections at different grain sizes (e.g. phonemes, onset-rimes, syllables). In addition, we found that the conflicting conditions had lower accuracy, slower reaction time and greater activation in left inferior frontal gyrus as compared to non-conflicting conditions. Higher accuracy was also correlated greater activation in left inferior frontal gyrus for the most difficult conflicting condition (e.g. jazz-has). The finding of both a conflict effect and a correlation with accuracy in left inferior frontal gyrus suggests that this region may be involved in resolving the conflict between orthographic and phonological representations.
Strid JE & Booth JR (2007). Visual word access in monolinguals and bilinguals in English and Spanish. Journal of Psycholinguistic Research, 36, 383-409. [pdf]
Two experiments examined if visual word access varies cross-linguistically by studying Spanish/English adult bilinguals, priming two syllable CVCV words both within (Experiment 1) and across (Experiment 2) syllable boundaries in the two languages. Spanish readers accessed more first syllables based on within syllable primes compared to English readers. In contrast, syllable based primes helped English readers recognize more words than in Spanish, suggesting that experienced English readers activate a larger unit in the initial stages of word recognition. Primes spanning the syllable boundary affected readers of both languages in similar ways. In this priming context, primes that did not span the syllable boundary helped Spanish readers recognize more syllables, while English readers identified more words, further confirming the importance of the syllable in Spanish and suggesting a larger unit in English. Overall, the experiments provide evidence that readers use different units in accessing words in the two languages.
Booth JR (2007). Brain bases of learning and development of language and reading. In D Coch, G Dawson & KW Fischer (Eds), Human Behavior, Learning and the Developing Brain (pp. 279-300). Guilford Press. [pdf]
The purpose of this chapter is to review what is known about the development of neurocognitive networks for language and reading. The chapter will focus on age-related changes in orthographic, phonological, semantic, and syntactical processing. Particular attention will be paid to how these different representational systems are integrated by posterior heteromodal cortex and how anterior systems in the inferior frontal gyrus may modulate these processes. Throughout this chapter, we will examine whether learning mechanisms in adults are similar to developmental changes. Similarities between learning and development would support the skill-learning hypothesis that the neural basis of behavioral and cognitive development in children is the same as skill acquisition in adults.
Booth JR, Wood L, Lu D, Houk J & Bitan T (2007). The role of the basal ganglia and cerebellum in language processing. Brain Research, 1133, 136-144. [pdf]
The roles of the cerebellum and basal ganglia have typically been confined in the literature to motor planning and control. However, mounting evidence suggests that these structures are involved in more cognitive domains such as language processing. In the current study, we looked at effective connectivity (the influence that one brain region has on another) of the cerebellum and basal ganglia with regions thought to be involved in phonological processing, i.e. left inferior frontal gyrus and left lateral temporal cortex. We analyzed functional magnetic resonance imaging data (fMRI) obtained during a rhyming judgment task in adults using dynamic causal modeling (DCM). The results showed that the cerebellum has reciprocal connections with both left inferior frontal gyrus and left lateral temporal cortex, whereas the putamen has unidirectional connections into these two brain regions. Furthermore, the connections between cerebellum and these phonological processing areas were stronger than the connections between putamen and these areas. This pattern of results suggests that the putamen and cerebellum may have distinct roles in language processing. Based on research in the motor planning and control literature, we argue that the putamen engages in cortical initiation while the cerebellum amplifies and refines this signal to facilitate correct decision making.
Booth JR, Bebko G, Burman DD & Bitan T (2007). Children with reading disorder show modality independent brain abnormalities during semantic tasks. Neuropsychologia, 45, 775-783. [pdf]
Neuroimaging studies have suggested that left inferior frontal gyrus, left inferior parietal lobule and left middle temporal gyrus are critical for semantic processing in normal children. The goal of the present functional magnetic resonance imaging (fMRI) study was to determine whether these regions are systematically related to semantic processing in children (9- to 15-year-olds) diagnosed with reading disorders (RD). Semantic judgments required participants to indicate whether two words were related in meaning. The strength of semantic association varied continuously from higher association pairs (e.g., king - queen) to lower association pairs (e.g. net – ship). We found that the correlation between association strength and activation was significantly weaker for RD children compared to controls in left middle temporal gyrus and left inferior parietal lobule for both the auditory and the visual modalities and in left inferior frontal gyrus for the visual modality. These results suggest that the RD children have abnormalities in semantic search/retrieval in the inferior frontal gyrus, integration of semantic information in the inferior parietal lobule and semantic lexical representations in the middle temporal gyrus. These deficits appear to be general to the semantic system and independent of modality.
