Biology subjects

Wiesman, A. I.

Publications and source records attributed to Wiesman, A. I..

3 recordsLinked to original sources

bioRxiv2026

Resting Cortical Alpha and Beta Oscillations are Continuous Across Space and Frequency

Cortical alpha and beta oscillations are traditionally conceptualized as spatially distinct, with alpha rhythms constrained to the occipital cortex and beta rhythms to frontal cortices. Little work has tested this spatial separability empirically and explored whether the distribution of these cortical rhythms may be continuous in space and frequency. Using task-free magnetoencephalography of 604 participants and density-based unsupervised clustering of individual spatio-spectral peaks, we show that the distribution of cortical oscillatory activity across the alpha-to-beta frequency range is structured along a continuous spatio-spectral gradient from occipitotemporal to frontal cortices. Across individuals, the expression of this gradient correlates positively with cognition and decays with age. This work introduces a continuous spatio-spectral organizational structure linking alpha- and beta-band activity across all lobes of the neocortex, with a potential role in flexible segregation and integration of communication between sensorimotor regions of the brain.

neuroscience↗

bioRxiv2026

Chemoarchitectural influences on the cortical connectome confer resilience in aging

The macroscale signaling of the brain emerges from the integration of connected areas, orchestrated by microscale, regional molecular processes. Despite growing multimodal neuroimaging data resources, the role of cortical chemoarchitecture in shaping inter-regional functional connectivity remains poorly understood. Here, we examine whether brain regions that share a chemoarchitectural signature exhibit strong frequency-resolved functional connectivity, and whether aging moderates this neurochemical-functional alignment. Using magnetoencephalography data from across the healthy adult lifespan (n = 569), we identify a frequency-dependent organization of functional connectivity by slow neuromodulator systems, with low-frequency bands ({theta}-) shaped most strongly by noradrenergic systems, and faster ({beta}) alignment dependent on serotonergic chemoarchitecture. Aging strengthens the influence of neurochemistry on inter-regional connectivity, with frequency-specific implications for age-related cognitive performance. Neurochemical influences on{theta} -band connectivity were associated with worse cognition in older adults, while the opposite was true for the low-{gamma} ({gamma}{downarrow}) band. This suggests that neuromodulatory preservation of high-frequency dynamics in older adults may reflect neural resilience. Together, our findings indicate that neurochemical-functional alignment is frequency-dependent, distinguishing between maladaptive and resilient modes of brain organization.

neuroscience↗

bioRxiv2021

Stability of spectral estimates in resting-state magnetoencephalography: recommendations for minimal data duration with neuroanatomical specificity

The principle of resting-state paradigms is appealing and practical for collecting data from impaired patients and special populations, especially if data collection times can be minimized. To achieve this goal, researchers need to ensure estimated signal features of interest are robust. In electro- and magnetoencephalography (EEG, MEG) we are not aware of studies of the minimal length of recording required to yield a robust one-session snapshot of the frequency-spectrum derivatives that are typically used to characterize the complex dynamics of the brains resting-state. We aimed to fill this knowledge gap by studying the stability of common spectral measures of resting-state MEG source time series obtained from large samples of single-session recordings from shared data repositories featuring different recording conditions and instrument technologies (OMEGA: N = 107; Cam-CAN: N = 50). We discovered that the rhythmic and arrhythmic spectral properties of intrinsic brain activity can be robustly estimated in most cortical regions when derived from relatively short recordings of 30-s to 120-s of resting-state data, regardless of instrument technology and resting-state paradigm. Using an adapted leave-one-out approach and Bayesian analysis, we also provide evidence that the stability of spectral features over time is unaffected by age, sex, handedness, and general cognitive function. In summary, short MEG sessions are sufficient to yield robust estimates of frequency-defined brain activity during resting-state. This study may help guide future empirical designs in the field, particularly when recording times need to be minimized, such as with patient or special populations.

neuroscience↗