Biology subjects

Yarbrough, J. B.

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

3 recordsLinked to original sources

bioRxiv2025

Distributed theta networks support the control of working memory: Evidence from scalp and intracranial EEG

We combined scalp EEG and intracranial EEG (iEEG) to identify spectral and network-level signatures of executive control during a delayed match-to-sample task working memory task. To isolate executive processes, we contrasted test and sample phases, matched in perceptual input but differing in cognitive demand. Scalp EEG revealed increased frontal midline theta event-related spectral perturbations (ERSPs), dynamic increases and decreases in posterior theta-alpha ERSPs, and decreased central alpha-beta ERSPs during the test phase. These local spectral changes were accompanied by enhanced frontoposterior theta phase synchrony and network hub strength, predicting higher behavioral accuracy. Using a novel cross-modal scalp EEG-iEEG ERSP similarity approach, we localized the sources of scalp-derived frontal midline, posterior, and central control effects to medial frontal, parietal, temporal, and occipital regions. Our results integrate power and connectivity measures across scalp and iEEG, linking local spectral fluctuations to broader network organization. Together, they support a model in which executive control emerges from flexible, temporally precise coordination between medial frontal control hubs and posterior representational systems.

neuroscience↗

bioRxiv2025

High frequency broadband activity detected noninvasively in infants distinguishes wake from sleep states

High frequency broadband activity (HFB; 70-150 Hz) indexes local brain activity. It is predominantly studied using invasive measures due to signal drop off from skull attenuation. We hypothesized that HFB is detectable in infants noninvasively through fontanelles and thin skull that have not fully developed. We analyzed scalp electroencephalography (EEG) data during wake and sleep states in 19 channels from 18 infants (1-4 months, both sexes). At the group level, linear mixed-effects models revealed greater HFB power in wake versus sleep states in midline and central channels near fontanelles, as well as in occipital channels over thin skull. These differences were detected with 90% reliability using as few as 25 seconds of data per state in as few as 10 subjects. On the individual level, linear mixed-effects models revealed the same wake > sleep effect with a mean reliability of 60% when using at least 50 seconds of data per state. These findings establish that noninvasive HFB detection in infants is not only possible at sites where the skull has not fully developed, but sufficiently robust to enable systematic investigation of early cognitive development.

neuroscience↗

bioRxiv2025

One of these things is not like the others: Theta, beta, & ERP dynamics of mismatch detection

Working memory (WM) enables the detection of mistakes by permitting one to notice when sensory input is mismatched to their internal prediction. Prior studies support the role of frontal midline theta activity, with an overlapping N200 event-related potential (ERP), as a mechanism for comparing incoming sensory stimuli to the internal model. Additionally, posterior low-beta activity has been proposed as a mechanism for processing incoming sensory stimuli in WM. However, it is unknown whether frontal midline theta activity and the N200 support mismatch detection, or whether posterior low-beta activity extends from sensory processing to detecting a mismatch between sensory input and the internal model. Here, we reveal that frontal midline theta supports mismatch detection and explains individual WM performance. Unexpectedly, instead of the N200, results show a positive slow wave ERP overlapping with the frontal midline theta mismatch response. Results additionally indicate a late posterior low-beta response persisting from stimulus presentation into the post-stimulus delay. Our findings establish frontal midline theta as a marker of successful mismatch detection, challenge the domain-general role of the N200 in error detection, and support theories linking posterior low-beta to processing incoming sensory stimuli.

neuroscience↗