Biology subjects

Pattamadilok, C.

Publications and source records attributed to Pattamadilok, C..

5 recordsLinked to original sources

bioRxiv2024

Reading Acquisition Drives Linguistic Cross-Modal Convergence in The Left Ventral Occipitotemporal Cortex

Reading acquisition requires linking visual symbols with speech sounds, leading to the development of neural sensitivity to print. While prior studies have shown the importance of cross-modal integration in spoken language areas, the higher-level visual area (lvOT) processing printed words remained more context-dependent. This longitudinal study investigated whether the lvOT undergoes cross-modal reorganization to facilitate print-speech integration during reading development and how these changes relate to reading skills. We followed children over two years, beginning at the onset of formal reading instruction. We examine lvOT responses to print-specific, speech-specific, and its convergence at whole-brain, region of interest and voxel-based levels. Results showed that with reading experience, the Initial print-specific responses in the lvOT are transformed into responses to both print and speech input. This transformation positively correlates with reading skills, especially in early acquisition stages. These findings suggest that reading acquisition drives cross-modal reorganization within the lvOT, enabling the area to integrate print and speech. They shed light on the broader neural mechanisms supporting reading development.

neuroscience↗

bioRxiv2024

Learning to read transforms phonological into phonographic representations: Evidence from a Mismatch Negativity study

Learning to read changes the nature of speech representation. One possible change consists in transforming phonological representations into phonographic ones. However, evidence for such transformation remains surprisingly scarce. Here, we used a novel word learning paradigm to address this issue. During a learning phase, participants were exposed to unknown words in both spoken and written forms. Following this phase, the impact of spelling knowledge on spoken input perception was assessed at two time points through an unattended oddball paradigm, while the Mismatch Negativity component was measured by high density EEG. Immediately after the learning phase, no influence of spelling knowledge on the perception of the spoken input was found. Interestingly, one week later, this influence emerged, making similar sounding words with different spellings more distinct than similar sounding words that also share the same spelling. Our finding provides novel neurophysiological evidence of an integration of phonological and orthographic representations that occurs once newly acquired knowledge has been consolidated. These novel phonographic representations may characterize how known words are stored in literates mental lexicon.

neuroscience↗

bioRxiv2024

Revealing the co-existence of written and spoken language coding neural populations in the left-ventral occipitotemporal cortex

Reading relies on the ability to map written symbols with speech sounds. The left ventral occipitotemporal cortex (left-vOT) plays a crucial role in this process. Through the automatization of the mapping ability, this specific part of the ventral visual pathway (a.k.a., the Visual Word Form Area) progressively becomes specialized in written word recognition. Yet, despite its key role in reading, the area also responds to speech. This observation raises questions about the actual nature of neural representations encoded in the left-vOT and, therefore, the underlying mechanism of the cross-modal responses. Here, we addressed this issue by applying fine-grained analyses of within- and cross-modal repetition suppression effects (RSEs) and Multi-Voxel Pattern Analyses in fMRI and sEEG experiments. Convergent evidence across analysis methods and protocols showed significant RSEs and successful decoding in both within-modal visual and auditory conditions suggesting that subpopulations of neurons within the left-vOT distinctly encode written and spoken language inputs. This functional organization of neural populations enables the area to respond to speech input directly and indirectly, i.e., after speech sounds are converted to orthographic representations. The finding opens further discussions on how the human brain may be prepared and adapted for an acquisition of a complex ability such as reading. Significance StatementLearning to read generates new functional responses in neurons in the left ventral visual pathway. Soon after reading acquisition, these neurons become specialized in processing known scripts, thus leading to the functional designation of the "Visual Word Form Area" (VWFA). However, controversies remain regarding the nature of neural representations encoded in this "reading" region, as its activation to speech is also reported. We investigate the neural mechanism(s) underlying these bimodal responses using within and cross-modal repetition suppression and decoding protocols. fMRI and sEEG experiments provided converging evidence indicating that, despite its specialization in reading, VWFA also contained subpopulations of neurons that encode speech. This functional organization could reveal why neurons at this anatomical location are ideal for reading acquisition.

neuroscience↗

bioRxiv2022

Graph theoretical analysis reveals the adaptive role of the left ventral occipito-temporal cortex in the brain networks during speech processing

The left ventral occipito-temporal cortex (left-vOT) plays a key role in reading. Several studies have also reported its activation during speech processing, suggesting that it may play a role beyond written word recognition. Here, we adopt a graph theoretical analysis to investigate the functional role of this area in the whole-brain network while participants processed spoken sentences in different tasks. We find that its role and interactions with other areas changes in an adaptive manner. In a low-level speech perception task, the left-vOT is part of the visual network and acts as a connector that supports the communication with other cognitive systems. When speech comprehension is required, the area becomes a connector within the sensorimotor-auditory network typically recruited during speech processing. However, when comprehension is compromised due to degradation of speech input, the area disengages from the sensorimotor-auditory network. It becomes part of the visual network again and turns from connector into a simple peripheral node. These varying connectivity patterns are coherent with the Interactive Account considering the left-vOT as a convergent zone with multiple functions and interaction patterns that depend on task demands and the nature of sensory input.

neuroscience↗

bioRxiv2020

The cerebellum is involved in internal and external speech error monitoring

An fMRI study examined how speakers inspect their own speech for errors. In a word production task, we observed enhanced involvement of the right posterior cerebellum for trials that were correct, but on which participants were more likely to make a word-as compared to a non-word error. Furthermore, comparing errors to correctly produced utterances, we observed increased activation of the same cerebellar region, in addition to temporal and medial frontal regions. Within the framework associating the cerebellum to forward modelling of upcoming actions, this indicates that forward models of verbal actions contain information about word representations used for error monitoring even before articulation (internal monitoring). Additional resources relying on speech perception and conflict monitoring are deployed during articulation to detect overt errors (external monitoring). In summary, speech monitoring seems to recruit a network of brain regions serving domain general purposes, even for abstract levels of processing.

neuroscience↗