Biology subjects

Hancock, R.

Publications and source records attributed to Hancock, R..

5 recordsLinked to original sources

bioRxiv2025

EEG-derived Brain Connectivity in Theta/Alpha Frequency Bands Increases During Reading of Individual Words

ObjectiveAlthough extensive insights about the neural mechanisms of reading have been gained via magnetic and electrographic imaging, the temporal evolution of the brain network during sight reading remains unclear. We tested whether the temporal dynamics of the brain functional connectivity involved in sight reading can be tracked using high-density scalp EEG recordings. ApproachTwenty-eight healthy subjects were asked to read words in a rapid serial visual presentation task while recording scalp EEG, and phase locking value was used to estimate the functional connectivity between EEG channels in the theta, alpha, beta, and gamma frequency bands. The resultant networks were then tracked through time. Main resultsThe networks graph density gradually increases as the task unfolds, peaks 150-250-ms after the appearance of each word, and returns to resting-state values, while the shortest path length between non-adjacent functional areas decreases as the density increases, thus indicating that a progressive integration between regions can be detected at the scalp level. This pattern was independent of the words type or position in the sentence, occurred in the theta/alpha band but not in beta/gamma range, and peaked earlier in the alpha band compared to the theta band (alpha: 184{+/-}61.48-ms; theta: 237{+/-}65.32-ms, P-value P<0.01). Nodes in occipital and frontal regions had the highest eigenvector centrality throughout the words presentation, and no significant lead-lag relationship between frontal/occipital regions and parietal/temporal regions was found, which indicates a consistent pattern in information flow. In the source space, this pattern was driven by a cluster of nodes linked to sensorimotor processing, memory, and semantic integration, with the most central regions being similar across subjects. SignificanceThese findings indicate that the brain network connectivity can be tracked via scalp EEG as reading unfolds, and EEG-retrieved networks follow highly repetitive patterns lateralized to frontal/occipital areas during reading.

neuroscience↗

bioRxiv2025

Computational Methods for Optimal Coil Placement and Maximization of Lobule-Focused Cortical Activation in Cerebellar TMS

BackgroundCoil placement on the cerebellum lacks accuracy in targeting the intended lobules and limits the efficacy of cerebellar transcranial magnetic stimulation (TMS) in treating movement disorders. ObjectiveDevelop a multiscale computational pipeline and method to rapidly predict the cellular response to cerebellar TMS and optimize the coil placement accordingly for lobule-specific activation. MethodsThe pipeline integrates 3T T1/T2-weighted MRI scans of the human cerebellum, lobule parcellation, and finite element models of the TMS-induced electric (E-) fields for figure-of-eight coils (MagStim D70) and double-cone coils (Deymed 120BFV). A constrained optimization method is developed to estimate the fiber bundles from cerebellar cortices to deep nuclei and, for both coil types, find the coil placement and orientation that maximize the E-field intensity in a user-selected lobule. Multicompartmental Purkinje cell models with realistic axon geometries and Gaussian process regression are added to predict the recruitment in the Purkinje layer. ResultsOur pipeline was tested in five individuals to target the left lobule VIII and resulted in normalized E-field intensities at the target 49.6{+/-}25.6% (D70) and 29.3{+/-}17.7% (120BFV) higher compared to standard coil positions (i.e., 3 cm left, 1 cm below the inion), mean{+/-}S.D. The minimum pulse intensity to recruit Purkinje cells on a 4 mm2-surface in the target decreased by 21.6% (range: 4.7-55.0%) and 10.7% (range: 7.9-18.2%), and the spillover to adjacent lobules decreased by 70.6{+/-}16.3% and 71.7{+/-}20.8% compared to standard positions (D70 and 120BFV, respectively). ConclusionOur tools are effective at targeting specific lobules and pave the way toward patient-specific setups.

neuroscience↗

bioRxiv2023

Association between recovering from tempo perturbations and reading measurements.

A strong correlation between auditory temporal processing and reading proficiency has been consistently observed across clinical and nonclinical populations, spanning various age groups and languages. Specifically, rhythm sensitivity in both the music and speech domains has been considered to be fundamental for accurately tracking the hierarchical acoustic components in speech, playing a central role in the development of reading skills. However, the empirical validation of this hypothesis has primarily utilized stimuli with an isochronous underlying beat structure, which is limited in its ability to capture the nonlinearity inherent in the perception of timing within the speech and music domains. In our current study, we introduced perturbation stimuli and demonstrated a relationship between sensorimotor synchronization performance and reading measurements in the neurotypical adult population. Specifically, the current study highlighted that sensorimotor synchronization during the post-perturbation time window yields notably superior predictive value across a wide array of reading measurements when compared to the pre-perturbation time window, which, in contrast, did not predict reading measurements. Furthermore, our novel curve fitting analysis effectively captured the nonlinear aspects of participants sensorimotor synchronization performance when recovering from tempo perturbation, providing further insight into their auditory temporal processing abilities when responding to timing changes in auditory signals--a phenomenon commonly encountered in both speech and music contexts.

neuroscience↗

bioRxiv2023

Bayesian analysis of resting-state temporal low-γ power in children with phonemic decoding deficits and certain comorbidities

Dyslexia (decoding-based reading disorder, or RD) is a common learning disorder affecting a large proportion of the population. One theory of the origins of reading deficits is a language network which cannot effectively entrain to speech, with cascading effects on the development of phonological skills. Low-gamma (low-{gamma}, 30-45 Hz) neural activity is thought to correspond to tracking at phonemic rates in speech. The main goals of the current study were to investigate temporal low-{gamma} band-power during rest in a sample of children and adolescents with and without RD. We used a Bayesian statistical approach, which has become increasingly popular in the field for its ability to quantify the relative likelihood of competing hypotheses. We examined whether (1) resting-state temporal low-{gamma} power was attenuated in the left temporal region in those with RD; (2) low-{gamma} power covaried with individual performance in reading skills; (3) low-{gamma} temporal lateralization was atypical in the group with RD. Results did not support the hypothesized effects of RD status and poor phonemic decoding ability on left hemisphere low-{gamma} power or lateralization: post-hoc tests revealed that the lack of atypicality in the RD group was not due to the inclusion of those with comorbid attentional deficits. However, post-hoc tests also revealed a specific left-dominance for low-{gamma} rhythms in the RDs only when participants with attentional deficits were excluded. We also observed an inverse relationship between phonemic decoding and left-lateralization in the controls, such that those with better decoding skills were less likely to show left-lateralization, contrary to our expectations. We discuss these unexpected findings in the context of prior theoretical frameworks on temporal sampling, and suggest that our null findings in resting-state EEG may reflect the importance of real-time language processing to evoke gamma rhythms in the phonemic range during childhood and adolescence.

neuroscience↗

bioRxiv2020

Advanced paternal age effect on offspring's reading ability: The mediating role of thalamic maturation

The importance of (inherited) genetic impact in reading development is well-established. De novo mutation is another important contributor that is recently gathering interest as a major liability of neurodevelopmental disorders, but has been neglected in reading research to date. Paternal age at childbirth (PatAGE) is known as the most prominent risk factor for de novo mutation, which has been repeatedly shown by molecular genetic studies. As one of the first efforts, we performed a preliminary investigation of the relationship between PatAGE, offsprings reading, and brain structure in a longitudinal neuroimaging study following 51 children from kindergarten through third grade. The results showed that greater PatAGE was associated significantly with worse reading, explaining an additional 9.5% of the variations after controlling for a number of confounds--including familial factors and cognitive-linguistic reading precursors. Moreover, this effect was mediated by volumetric maturation of the left posterior thalamus from ages 5 to 8. Complementary analyses indicated the PatAGE-related thalamic region was most likely located in the pulvinar nuclei and related to the dorsal attention network by using brain atlases, public datasets, and offsprings diffusion imaging data. Altogether, these findings provide novel insights into neurocognitive mechanisms underlying the PatAGE effect on reading acquisition during its earliest phase and suggest promising areas of future research. HighlightsO_LIPaternal age at childbirth (PatAGE) is negatively correlated with offsprings reading abilities. C_LIO_LIPatAGE is related to volumetric maturation of the left posterior thalamus. C_LIO_LIThalamic development mediates the PatAGE effect on reading. C_LIO_LIThe PatAGE-related thalamic area is more likely to connect with the dorsal attention network. C_LI

neuroscience↗