Biology subjects

Feltham, G.

Publications and source records attributed to Feltham, G..

4 recordsLinked to original sources

bioRxiv2026

Atypical cortical encoding of the low-frequency temporal dynamics of natural speech identifies children with Developmental Language Disorder

Developmental Language Disorder (DLD) is a neurodevelopmental condition that causes significant difficulties in understanding and using spoken language. Here we use electroencephalography (EEG) recorded during natural speech listening with 9-year-old children to identify dynamic neural processing patterns that characterize children with DLD compared to typically-developing age-matched controls. We applied Principal Components Analysis (PCA) to identify spatial ensembles of channels that represented distinct (uncorrelated) sources of cortical activity, and explored phase-amplitude coupling (PAC) between delta (0.5-4 Hz), theta (4-8 Hz) and low-gamma (25-40 Hz) oscillations. We then isolated EEG common spatial patterns (CSP) that identified children with DLD. The PAC analyses identified the delta band as a key source of group differences, and only delta-low gamma PAC differed significantly between participant groups. The CSP analyses also identified the delta band as a key mechanistic source of group differences. The findings are suggestive of distinct atypical low-frequency neural dynamics during speech encoding for children with DLD, which could be targeted by novel interventions.

neuroscience↗

bioRxiv2025

The renin angiotensin system in cognitive flexibility: Effects of single-dose losartan on task-switching in healthy volunteers

IntroductionCognitive flexibility, defined as the ability to shift mental strategies when environmental demands change, may influence psychological well-being and psychiatric treatment outcomes. Emerging research increasingly implicates the renin angiotensin system (RAS) in cognition, yet its role in cognitive flexibility is inadequately understood. MethodsWe conducted a double-masked trial with N=60 healthy adults aged 18-50. Participants were randomly assigned to receive a single 50 mg dose of losartan, an angiotensin II receptor blocker, or placebo. Following a waiting period, participants completed a task-switching paradigm as a measure of cognitive flexibility, which required dynamically categorizing arrows based on location or direction. Statistical analyses were conducted to determine group (losartan vs. placebo), task (location vs. direction), and switch (switching vs. repeating a task) effects on reaction time (RT) and accuracy independently. A composite bin score was also computed, integrating both RT and accuracy data. ResultsAll participants displayed the expected switch costs. While participants on losartan exhibited numerically superior RTs and accuracy, losartan did not significantly improve task-switching performance relative to placebo. This was confirmed by the bin score analysis, which indicated no benefit of losartan when RT and accuracy were considered together. An exploratory probe suggested that losartan improved accuracy on direction switch trials, indicating a potential drug effect under specific cognitive conditions. ConclusionOverall, we found no significant benefits of losartan on task-switching in healthy adults. Our results may be explained by ceiling effects in our sample, which could have hindered the detection of group differences, or possibly reflect a negligible role for the RAS in cognitive flexibility.

neuroscience↗

bioRxiv2025

Neural processing of natural speech by children with developmental language disorder (DLD): EEG speech decoding, power and classifier investigations

The sensory/neural Temporal Sampling (TS) theory of developmental language disorder (DLD) is based on the sensory and linguistic impairments in rhythm processing that are found in children with both developmental dyslexia (DD) and DLD. These sensory/linguistic impairments include decreased sensitivity to amplitude rise times (ARTs, the sensory triggers related to automatic cortical speech tracking), syllable stress patterns and speech rhythm. At the neural level TS theory predicts impairments in the cortical tracking of different rates of amplitude modulation (AM) in the speech signal <10Hz. To date, the accuracy of low-frequency cortical tracking in natural continuous speech has not been measured in children with DLD. Here, EEG was recorded during story listening from children with and without DLD aged around 9 years, and decoding analyses in the delta, theta and alpha (control) bands were carried out. EEG power was computed in the delta, theta and gamma bands, and phase-amplitude coupling and phase-phase coupling (PAC, PPC) were also computed between bands. Whole-brain analyses showed that the accuracy of low-frequency decoding (delta, theta) did not differ between groups. However, region-specific analyses revealed significantly reduced delta-band speech tracking in the right temporal cortex in the children with DLD. PAC and PPC dynamics did not differ between groups. The data suggest that low-frequency cortical tracking impairments in DLD may be spatially constrained to the right hemisphere rather than globally present as in DD. The data are discussed using TS theory. HighlightsO_LICortical tracking of natural speech is measured in children with and without DLD C_LIO_LIDelta-band tracking is impaired in right temporal regions in children with DLD C_LIO_LICross-frequency coupling dynamics (PAC, PPC) did not differ between groups C_LI

neuroscience↗

bioRxiv2024

Investigating the 'Atypical Rhythm Risk' hypothesis in children with developmental language disorder using an EEG rhythmic speech paradigm

Sensitivity to rhythmic and prosodic cues in speech has been described as a precursor of language acquisition. Consequently, atypical rhythmic processing during infancy and early childhood has been considered a risk factor for developmental language disorders. Despite many behavioural studies, the neural processing of rhythmic speech has not yet been explored in children with developmental language disorder (DLD). Here we utilise EEG to investigate the neural processing of rhythmic speech by 9-year-old children with and without DLD. In the current study, we investigate phase entrainment, angular velocity, power, event related potentials (ERPs), phase-amplitude coupling (PAC) and phase-phase coupling (PPC), at three frequency bands selected on the basis of the prior literature, delta, theta and low gamma. We predicted a different phase of entrainment in the delta band in children with DLD, and also greater theta power, atypical cross-frequency coupling and possibly atypical gamma-band responses. Contrary to prediction, children with DLD demonstrated significant and equivalent phase entrainment in the delta and theta bands to control children. However, only the control children showed significant phase entrainment in the low gamma band. The children with DLD also exhibited significantly more theta and low gamma power compared to the control children, and there was a significant gamma-band difference in angular velocity between the two groups. Finally, group resultant phase analyses showed that low-frequency phase (delta and theta) affected gamma oscillations differently by group. These EEG data show important differences between children with and without DLD in the neural mechanisms underpinning the processing of rhythmic speech. The findings are discussed in terms of auditory theories of DLD, particularly Temporal Sampling theory.

neuroscience↗