Biology subjects

Cash, R.

Publications and source records attributed to Cash, R..

3 recordsLinked to original sources

bioRxiv2026

Individualized Functional Connectivity-Guided TMS Targeting Theory of Mind Network for Autism Spectrum Disorder

Transcranial magnetic stimulation (TMS) shows promise in autism spectrum disorder (ASD), but variable outcomes may reflect suboptimal targeting. We developed a functional-connectivity (FC)-guided individualized TMS approach by identifying an ASD-relevant effective region and selecting superficial targets. In a multi-site mega-analysis of Autism Brain Imaging Data Exchange I data (298 ASD, 348 controls), the region with the greatest regional homogeneity (ReHo) abnormality was defined as the effective region. Individualized dorsolateral prefrontal cortex (DLPFC) and inferior parietal lobule (IPL) targets were localized as sites with strongest FC to this region. Group differences, symptom associations, and a six-patient case series were examined. The posterior cingulate cortex (PCC) showed the greatest ReHo abnormality and was implicated in theory-of-mind (ToM) circuitry. PCC-guided targets showed weaker FC in ASD in the right IPL, correlating with Autism Diagnostic Interview social scores; left DLPFC FC differences lacked symptom associations. In the case series, individualized PCC-IPL-guided TMS reduced ToM-related symptoms and Childhood Autism Rating Scale scores. PCC-IPL FC-guided TMS is a biologically informed intervention for modulating ToM circuitry in ASD.

neuroscience↗

bioRxiv2024

Event-marked Windowed Communication: Inferring activity propagation from neural time series

Tracking signal propagation in nervous systems is crucial to our understanding of brain function and information processing. Current methods for inferring neural communication track patterns of sustained co-activation over time, making them unsuitable to detect discrete instances of signal transmission. Here, we propose Event-marked Windowed Communication (EWC), a new analytical framework to infer functional interactions arising from discrete signalling events between neural elements, in otherwise continuous time series data. In contrast to conventional measures of functional connectivity, our method utilises an event-based subsampling of neural time series, which allows it to capture the statistical analogue of activity propagation. We test EWC on simulations of neural dynamics and show that it is capable of retrieving ground truth motifs of directional signalling, over a range of model configurations. Critically, we demonstrate that EWCs subsampling approach affords profound reductions in computation times, compared to established network inference methods such as transfer entropy. Lastly, we showcase the utility of EWC to infer whole-brain functional networks from MEG recordings. Networks computed using EWC and transfer entropy were highly correlated (median r=0.821 across subjects), but EWC inference was approximately 6.5 times faster per epoch. In summary, our work presents a new method to infer signalling from time series of neural activity at low computational costs. Our framework is flexible and can be applied to activity time series captured by diverse functional neuroimaging modalities, opening up new avenues for the study of neural communication.

neuroscience↗

bioRxiv2023

TMS-EEG shows mindfulness meditation is associated with an altered excitation/inhibition balance in the dorsolateral prefrontal cortex

ObjectiveMindfulness meditation is associated with functional brain changes in regions subserving higher order cognitive processes such as attention. However, no research to date has causally probed these areas in meditators using combined transcranial magnetic stimulation (TMS) and electroencephalography (EEG). This study aimed to investigate whether cortical reactivity to TMS differs in a community sample of experienced mindfulness meditators when compared to matched controls MethodsTMS was applied to the left and right dorsolateral prefrontal cortices (DLPFC) of 19 controls and 15 meditators while brain responses were measured using EEG. TMS-evoked potentials (P60 and N100) were analysed, and exploratory analyses using the whole EEG scalp field were performed to test whether TMS-evoked global neural response strength or the distribution of neural activity differed between groups. ResultsMeditators were found to have statistically larger P60/N100 ratios in response to left and right hemisphere DLPFC stimulation compared to controls (pFDR = 0.004, BF10 > 39). No differences were observed in P60 or N100 amplitudes when examined in isolation. We also found preliminary evidence for differences in the distribution of neural activity 269-332ms post stimulation. ConclusionThese findings demonstrate differences in cortical reactivity to TMS in meditators. Differences in the distribution of neural activity approximately 300ms following stimulation suggest differences in cortico-subcortical reverberation in meditators that may be indicative of greater inhibitory activity in frontal regions. This research contributes to our current understanding of the neurophysiology of mindfulness and highlights opportunities for further exploration into the mechanisms underpinning the benefits of mindfulness meditation.

neuroscience↗