Biology subjects

Ewen, J. B.

Publications and source records attributed to Ewen, J. B..

3 recordsLinked to original sources

bioRxiv2026

Auditory Evoked Potentials Differ from Controls and Correlate with Aspects of Cognition in Kabuki Syndrome and Rubinstein-Taybi Syndrome

Objective Kabuki syndrome (KS) and Rubinstein-Taybi syndrome (RSTS) are two disorders caused by dysfunctional components of the epigenetic machinery and both result in intellectual disability. Mouse models of both KS and RSTS have seen reversal of cognitive impairment with epigenetic treatments. However, a great need exists for biomarkers in these disorders to improve the likelihood of successful clinical trials. This study aimed to investigate cortical auditory evoked potentials (AEPs) in KS and RSTS so that it could potentially be developed into a response biomarker in the future. Methods The amplitude of the N1-P2-N2 complex was measured for passive listening to monotonal auditory stimuli in individuals with KS, with RSTS, and typically developing controls. A standardized cognitive assessment battery was performed and specific subtests were correlated with AEP values. Results Groups differed significantly in P2, N2, and P2-N2 amplitude although RSTS was consistently more different from typically developing controls than was KS. The mid- to late-phase AEP components (P2 and N2) also correlate with cognition within and across these groups particularly with language whereas earlier components N1 and P2 correlate more with measures of executive functioning. Conclusion Late-phase components of AEPs differ in KS and RSTS from each other and from controls. KS and RSTS differ from controls in P2 and N2 amplitude in the same direction and both show a positive correlation between language and P2 amplitude and a negative correlation between language and N2 amplitude. Together they also show an association with N1 and P2 amplitude and executive functioning. Significance AEPs may turn out to be a valuable response biomarker in KS and RSTS individually and together.

neuroscience↗

bioRxiv2021

Learning a new class of multisensory associations: High-density electrophysiological mapping of the temporal course of audio-visual object processing.

Multisensory objects that are frequently encountered in the natural environment lead to strong associations across a distributed sensory cortical network, with the end result experience of a unitary percept. Remarkably little is known, however, about the cortical processes sub-serving multisensory object formation and recognition. To advance our understanding in this important domain, the present study investigated the brain processes involved in learning and identification of novel visual-auditory objects. Specifically, we introduce and test a rudimentary three-stage model of multisensory object-formation and processing. Thirty adults were remotely trained for a week to recognize a novel class of multisensory objects (3D shapes paired to complex sounds), and high-density event related potentials (ERPs) were recorded to the corresponding unisensory (shapes or sounds only) and multisensory (shapes and sounds) stimuli, before and after intensive training. We identified three major stages of multisensory processing: 1) an early, multisensory, automatic effect (<100 ms) in occipital areas, related to the detection of simultaneous audiovisual signals and not related to multisensory learning 2) an intermediate object-processing stage (100-200 ms) in occipital and parietal areas, sensitive to the learned multisensory associations and 3) a late multisensory processing stage (>250 ms) that appears to be involved in both object recognition and possibly memory consolidation. Results from this study provide support for multiple stages of multisensory object learning and recognition that are subserved by an extended network of cortical areas.

neuroscience↗

bioRxiv2021

Associations Between Task-Related Modulation of Motor-Evoked Potentials and EEG Event-Related Desynchronization in Children with ADHD

Children with attention-deficit/hyperactivity disorder (ADHD) have previously shown a decreased magnitude of event-related desynchronization (ERD) during a finger-tapping task, with a large between-group effect. Because the neurobiology underlying several TMS measures have been studied in multiple contexts, we compared ERD and three TMS measures (Resting Motor Threshold [RMT], Short-Interval Cortical Inhibition [SICI] and Task-Related Up-Modulation [TRUM]) within 14 participants with ADHD (ages 8-12y) and 17 control children. The TD group showed a correlation between greater RMT and greater magnitude of alpha (10-13Hz, here) ERD, and there was no diagnostic interaction effect, consistent with a rudimentary model of greater needed energy input to stimulate movement. Similarly, inhibition measured by SICI was also greater in the TD group when the magnitude of movement-related ERD was higher; there was a miniscule diagnostic interaction effect. Finally, TRUM during a response-inhibition task showed an unanticipated pattern: in TD children, the greater TMS task modulation (TRUM) was associated with a smaller magnitude of ERD during finger-tapping. The ADHD group showed the opposite direction of association: greater TRUM was associated with larger-magnitude ERD. Prior EEG results have demonstrated specific alterations of task-related modulation of cortical physiology, and the current results provide a fulcrum for multimodal study.

neuroscience↗