Biology subjects

Headley, D. B.

Publications and source records attributed to Headley, D. B..

3 recordsLinked to original sources

bioRxiv2026

A UNIFORM CODING STRUCTURE IN THE CEREBRAL CORTEX

Prefrontal neurons simultaneously encode multiple task variables. While many studies reported that various groupings of task features could be detected at the population level, the combination of features encoded by individual neurons seemed random. Here, based on unit recordings with Neuropixel probes in behaving rats, we report that far from being random, the representation of information is highly structured. Specifically, the prefrontal network exhibits multiple coding gradients orthogonal to each other in a multidimensional representational space. In this coding structure, neurons have correlated absolute firing rate modulations by different variables, but the polarity of the modulation by one variable is not predictive of that by others. Moreover, this coding structure is manifest in tasks that probe different behavioral processes, ranging from defensive behaviors to sensory discrimination. Last, we find that the same structured representation is apparent in other neocortical regions, including associative and primary sensory areas.

neuroscience↗

bioRxiv2026

Precision phase targeting of event-related oscillations using real-time closed-loop TMS-EEG

ObjectiveCurrent closed-loop TMS-EEG systems rely on phase prediction algorithms that require highly periodic signals, limiting their ability to target brief, event-related activity. We developed a real-time closed-loop (RT-CL) TMS-EEG system that directly detects oscillatory phase without prediction, enabling phase-locked stimulation within microseconds. MethodsWe validated the system against a prediction-based approach using simulated sine waves and human EEG data (N=18), without active TMS delivery. ResultsAcross frequency-modulated sweeps and spontaneous occipital alpha oscillations (eyes-open vs. closed), the RT-CL system achieved higher triggering probability (11-24%) and reduced the phase error variability (2-10{degrees}). Importantly, when targeting event-related theta oscillations during two spatial navigation tasks, RT-CL produced [~]20% higher triggering probabilities and [~]17{degrees} lower phase error variability than phase prediction. ConclusionThese findings validate the RT-CL system for probing phase-dependent mechanisms during active cognition and pathological brain states. SignificanceBy precisely targeting brief, variable neural signals, RT-CL could be used for the development of personalized TMS interventions for neuropsychiatric disorders during symptom provocation.

neuroscience↗

bioRxiv2023

Oscillatory correlates of threat imminence during virtual navigation

The Predator Imminence Theory proposes that defensive behaviors depend on the proximity of a threat. While the neural mechanisms underlying this proposal have been well studied in animal models, it remains poorly understood in humans. To address this issue, we recorded EEG from twenty-four (15 female) young adults engaged in a first-person virtual reality Risk-Reward Interaction task. On each trial, participants were placed in a virtual room and then presented with either a threat or reward conditioned stimulus (CS) in the same room location (proximal) or different room location (distal). At a behavioral level, all participants learned to avoid the threat-CS, with most using the optimal behavior to actively avoid the proximal threat-CS (88% accuracy) and passively avoid the distal threat-CS (69% accuracy). By contrast, participants learned to actively approach the distal reward-CS (82% accuracy) and to remain still (passive) to the proximal reward-CS (72% accuracy). At an electrophysiological level, we observed a general increase in theta power (4-8 Hz) over right posterior channel P8 across all CS conditions, with the proximal threat-CS evoking the largest theta response. By contrast, distal CS cues induced two bursts of gamma (30-60 Hz) power over midline-parietal channel Pz (approx. 200 msec post-cue) and right frontal channel Fp2 (approx. 300 msec post-cue). Interestingly, while both bursts were sensitive to distal-CS cues, the first burst of gamma power was sensitive to the distal threat-CS requiring a passive response, and the second burst at channel Fp2 was sensitive to the distal reward-CS requiring an active response. Together, these findings demonstrate that oscillatory processes differentiate between the spatial proximity information during threat and reward encoding, likely optimizing the selection of the appropriate behavioral response.

neuroscience↗